This article attempts to give decent spell recommendations. Sorcerers in particular may find the following information helpful when deciding which spells to add to their repertoire.
Arcane spells[]
"Spells known" refers to how many spells a sorcerer can know from that level.
Level 0 (All spells known)
Flare - This spell is not limited by the target's HD, as opposed to daze.
Ray of frost - Does the most damage out of the level 0 spells (1d4+1 as opposed to 1d3)
Resistance - There are times when +1 to all saves comes in handy. One point equates to an additional 5% chance to avoid an effect.
Level 1 (5 spells known)
Identify - Invaluable for using items as soon as you pick them up, or in a low income environment.
Mage armor - Provides a +1 Dodge bonus to AC no matter what, unless you already have +20 to dodge.
Magic missile - A decent finisher that will save you the use of higher level spell. Also, one of the few spells that does magical damage.
Protection from alignment - The bonuses are almost too good to pass up. +2 to Armor (Deflection), +2 to all saves vs. Alignment, and Immunity to mind spells vs. Alignment. All in a level 1 spell!
Ray of enfeeblement - Deals 1d6+5 Strength damage, which stacks with negative energy burst.
True strike - A nice backup for casters using touch spells. Also obviously good for melee/archer types.
Level 2 (5 spells known)
Death armor - Does 1d4+5 points of magical damage on hit. Would be near useless if the damage was of a different type.
Eagle's splendor/fox's cunning - When maximized (or recast for the full effect), +2 to your DC, as well as other benefits of higher charisma/intelligence is nice.
Flame weapon - Melee types always love an extra 1d4+10 fire damage.
Invisibility - A general all-purpose hiding spell. Useful for "refreshing" improved invisibility, while leaving the higher spell slot available.
Knock - Who needs a rogue when you have this spell? Only works on locks not flagged as "Plot."
Melf's acid arrow - One of the only Level 2 direct damage spells, it's a nice opener against a tough target. The duration stacks all the way to Level 39, with damage being dealt over 13 rounds. Anything over 6 Acid Resist completely prevents all but the initial damage.
Ultravision/see invisibility - Both very useful to detect hidden entities (invisible or hiding in darkness).
Level 3 (4 spells known)
Displacement - 50% miss chance from melee/ranged attacks. A great way to artificially boost your AC, and therefore your survival. Also, unlike improved invisibility (which also provides 50% concealment), displacement does not get automatically dispelled when you walk into an invisibility purge area.
Find traps - The counterpart to knock. Some persistent worlds lower the effectiveness of this spell.
Flame arrow - 4d6 fire damage per arrow; spell resistance check for each arrow; one arrow per four levels. This spell is invaluable for tearing down spell mantles. It is also very efficient against enemies with low reflex saves and/or no evasion.
Greater magic weapon - A +5 enhancement bonus to a weapon is very welcome in some circumstances, especially low magic worlds.
Keen edge - Doubles the chance of critical hits in many cases. (The doubling assumes no feats affect the threat range, and there is no increase if used on a keen weapon.)
Vampiric touch - A wonderful spell, providing a relative shift of 120 hit points (60 damage plus 60 temporary hit points) at level 20+ maximized.
Level 4 (4 spells known)
Elemental shield - 50% resistance to fire and cold, as well as up to 1d6+40 flame damage on hit.
Evard's black tentacles - As this spell isn't "cast" on someone, it's impossible to be immune to it. Useful especially when empowered. (Note: Ethereal visage and perfect self negate all damage).
Ice storm - An area of effect spell that does NOT allow a reflex save for half/no damage. a solid 15d6 ice damage + 3d6 bludgeoning damage.
Improved invisibility - The effect of displacement, but much longer lasting and with invisibility! Note: Watch for the invisibility purge spell as it will remove your invisibility and your concealment.
Isaac's lesser missile storm - Slightly pitiful damage, but it deals "magical" damage.
Level 5 (4 spells known)
Bigby's interposing hand - Effectively +10 AC against a single target. A nice 45-50% miss chance unless that target has a wicked high Attack Bonus to begin with..
Energy buffer - The strongest of the "elemental shield" family. 40 damage per turn/60 max is a bit low though.
Firebrand - A 15d6 fireball that only hits hostile targets. A great crowd softener.
Lesser spell mantle - What some people don't realize is, in NWN, even if your mantle has one spell level left it will absorb up to a Level 9 spell. Great if you want to conserve higher level slots. At higher levels when "better protections" are available you can have a mantle that is hard to breach on the first try (there are 12 spells that are above it on the breach list).
Mestil's acid sheath - 1d6+80 damage on hit is usually more than the attacker can dish out himself. Combined with damage prevention (premonition, epic warding) this spell does wonders vs. monsters.
Level 6 (3 spells known)
Flesh to stone - A great "save or die" spell, as not many creatures have immunity to petrification.
Greater dispelling - Mainly useful for removing area effects, or counterspelling. Useless removing buffs cast by a level 24 spellcaster or higher (Spell check is 1d20+15 vs 12 + spell effect caster Level)
Greater spell breach - Useful for the opposite as greater dispelling. At the least, it removes greater spell mantle, premonition, spell mantle, and shadow shield. See breach for a full list of spells, and the order they are removed.
Isaac's greater missile storm - One of the major damage spells of any wizard/sorcerer's repertoire. Plenty of damage, with no save allowed. Works wonders maximized or empowered.
Undeath to death - The ultimate undead slaying spell. Valuable in undead-heavy areas, but useless otherwise.
Level 7 (3 spells known)
Banishment - Great against all those pesky outsider types, as well as summons, familiars, and animal companions. Useless if your module doesn't have a large number of the following: mephits, formians, slaadi, or any demon. Banishment will not work against rakshasa (immunity to spell level 8 and lower).This spell is not party-friendly (it will destroy allied familiars, summons, etc.).
Bigby's grasping hand - Wonderful at immobilizing that dangerous melee type while you pick him off. Tends to work more often than flesh to stone (requires a fortitude save) as it uses a specialized check (1d20 + 40 + 10 + 4 + (charisma or intelligence modifier). Assuming the caster has a bonus of +7 (24 Int/Cha), this translates to (1d20 + 61) Vs. (1d20 + BAB (max of 30 for a level 40 fighter) + strength modifier (max of 23 vs. half-orc fighter/RDD with +12 str. gear). This means, even against a tweaked out fighter, you always have a 40% advantage, not including the 1d20. Immunity to paralysis.
Finger of death - A good way to pick off minor non-death immune creatures. Even does damage to those who make their fortitude save (3d6 + uncapped caster level).
Protection from spells - A good general purpose shield. +8 to saves vs. spells translates to an additional 35-40% chance to make that save. Useful against save or die spells, such as Implosion.
Shadow shield - Immunity to negative energy, necromancy spells, +5 natural armor, and minor damage reduction (+3/10). Mostly used as a shield against harm and horrid wilting. A must have!
Level 8 (3 spells known)
Bigby's clenched fist - Fairly useful in PvP, as it prevents the opponent from resting. Even if it does 0 damage, it still "wakes" them up. Sadly, it also prevents you from resting, as you are considered to still be doing damage, regardless of the distance.
Greater planar binding - In a level 20 max environment, the celestial avenger (good) is one of the best summons, with gate falling not far behind. In a level 40 max environment, summons are nearly useless.
Greater sanctuary - The ultimate "bypass" spell. This spell makes you immune to all targeted spells and melee. However, you can still be pickpocketed or taunted, and area effects not targeting you (horrid wilting) still damage you, Whirlwind attack also works against you. There is currently a bug that does not allow improved invisibility and greater sanctuary to cooperate, so only use one or the other.
Horrid wilting - The main damage dealer of any wizard or sorcerer. It deals magical damage, and cannot be dodged by evasion.
Level 9 (3 spells known)
Bigby's crushing hand - Essentially a more powerful combination of Bigby's grasping hand and Bigby's clenched fist.
Dominate monster - In a non-mind immune environment, this spell is awesome. It effectively puts you two people ahead of the opposing team in PvM (Removes one from them, adds one to you). It's also entertaining to watch monsters duel to the death.
Mordenkainen's disjunction - If you're an arcane spellcaster without this, then you're in for a rough time. Essentially a mega strength Dispel and Breach.
Shapechange - Although underwhelming at first, shapechanging into a death slaad for the health regen and comboing with Mestil's acid sheath can win most encounters involving creatures with high resistances.
Time stop - So powerful, some persistent worlds actually prevent its use in some areas. Incredibly useful to keep an opponent from recasting their defences.
Wail of the banshee/weird Both wonderful spells, assuming you're not dealing with death immune creatures (or mind immune/fear immune in the case of weird, the paladin's aura of courage works also). Likely, the creatures with the more powerful treasure have both immunities, making this spell useful only for their henchmen.
Other spells worth mentioning:
Charm person/charm monster - If you're playing with anyone stupid (including the game AI), they will attack the charmed monster, effectively negating your spell. Useful when you're alone only.
Summon creature line of spells - You can only have one summoned creature. The best ones aren't in this family.
Balagarn's iron horn Very useful against low strength creatures, but the stun is good in theory only. In practice, one round is not a long time. Likely, you'll spend the extra spell (if hasted) enhancing the target's inability to make an action, so why not use that spell first?
Bull's strength - Unless you're a spellsword, this is only good for increasing your carrying capacity, or making strength checks.
Cat's grace - Good for increasing your AC, but you shouldn't be placing yourself in melee range to begin with.
Owl's wisdom - Good for will saves alone. These can mostly be prevented with mind immunity from protection from alignment or lesser mind blank.
Fireball - 10d6 isn't enough damage to write home about. The reflex save makes it vulnerable to evasion as well.
Negative energy burst- Deals 10 strength damage (caster level 40) over an area; the strength damage is not affected by the save. Avoid having friendly creatures in the area.
Mestil's acid breath - Most people don't have acid resist, so this is a nice spell to surprise them with. Sadly, it suffers the same weakness as Fireball.
Mind fog - a -10 penalty to will saves sounds nice, but the target needs to make a will save in order to take the penalty. Only useful if you plan to lure a creature back in forth across the cloud, in hopes they fail the save.
Chain lightning - A great spell, no doubt, but Issac's greater missile storm is more worth the spell slot. Chain lightning is great against multiple not-so-tough targets, but IGMS is better against one or two really tough ones.
Mass haste - Is the convenience of casting haste once worth an IGMS or a chain lightning? Simply take the normal haste spell, and cast that. On the other hand, you will become hugely popular if you use this spell in big parties on non-permahaste servers.
True seeing - It is see invisibility and ultravision combined. Unless you have lots of trouble with enemies dispelling the above, true seeing is better replaced with another spell.
Control undead - If your server has several incredibly strong undead, then take this. Otherwise, leave it.
Spell mantle - If you don't like recasting your lesser spell mantle every once in a while, then take this. If you play a sorcerer, it's a pretty expensive investment, as you only have 3 spells. Greater spell mantle is 1D12+10 (22 maximum) and empowered spell mantle is 1D8*1.5 + 12 (24 maximum). Then for the same spell level spell mantle is better.
Premonition - Useful in theory, or against small creatures. Not so much against anything with a +5 enhancement.
Sunburst - It would be a great spell if it did not have a reflex save. Still useful against undead.
Black blade of disaster - The price is too high for too little use. It takes a 9th level slot for one, you can't cast multiple blades, and you cannot even cast any other spell, or risk the blade disappearing. That, and its attack bonus is a maximum of 47, assuming you have a +20 bonus from your enhancement score. This spell might see some use when one is under the effects of greater sanctuary or if one is a melee caster. The good news is this spell is completely invulnerable to everything but the dismissal and Mordenkainen's disjunction.
Gate - If you consider a balor to be more useful than a different summon, then by all means use this spell. The only benefits I see is a one time casting of implosion. (Hopefully targeted where you want it.)
Power word, kill - Hard to determine when to use in my opinion. If actual Hit Points were shown above your enemies, then it would be more useful. Nonetheless, death immunity still prevents it.
Meteor swarm - 20d6 damage is nice, but the reflex save makes it a poor choice, especially for a high level spell. 10d6 on a successful save, and no damage with evasion. Melee types are generally within 5 feet of you anyways, so they don't take any damage whatsoever.
Energy drain - Is the step up from a level 4 spell (enervation) to a level 9 spell really worth an extra 1d4 levels drained? Take a maximized Enervation if you really want to lower your opponent's levels. Keep in mind Shadow Shield prevents both effects.
Divine spells[]
Level 0
Cure minor wounds - With a lot of this, you can cure a good number of hit points.
Resistance - There are times when +1 to all saves comes in handy. One point equates to an additional 5% chance to avoid an effect.