[Kaleban]

Here's my picks for a Sorcerer's spells (from top to bottom are priorities in each list, and this is at max level in ToB), and notes where appropriate:

1st Level
Magic Missile (good bang for the buck)
Chromatic Orb (un-saveable acid damage at 10th level, combine with Greater malison for greater effect)
Friends (Charisma boost is excellent for any encounter)
Protection from Petrification (quite a few Flesh to Stone Traps, and protects from Petrifying gazes of demons)
Free Slot (I usually pick Burning Hands for the fire damage)

2nd Level
Web (absolute excellent spell, good AoE, save penalty)
Blur (Ac and Save bonus)
Knock (imperative for un-bashable doors)
Mirror Image (good defensive spell)
Free Slot (usually Melf's Acid Arrow for spell disruption)

3rd level
Melf's Minute Meteors (excellent range weapon with +5 to hit)
Skull Trap (no damage cap, can be put to great effect popping in and out of invisibility with Staff of Magi to "round-up" bad guys)
Spell Thrust (for inevitable Wizard Duels)
Dispel Magic (an excellent general-purpose spell)
Free Slot (usually Flame Arrow, put in a Trigger and it can do MASSIVE damage)

4th level
Spider Spawn (combine with Web to make sushi out of your foes)
Stoneskin (absolute essential for the soloing sorcerer)
Greater Malison (essential for late game when saves are made frequently)
Spirit Armor (good AC bonus, but more important, a +3 to save vs. magic attacks!)
Free slot (usually Polymorph Self, Mustard jelly confers 100% magic resistance, or Secret Word if you cannot wait for Ruby Ray of Reversal)

5th level
Breach (Essential for enemies with buffing spellcasters)
Lower Resistance (needed for many late game bosses/enemies)
Animate Dead (15th level summon: Skeleton Warrior is AWESOME!)
Spell Immunity (an extremely potent and versatile spell... if used correctly)
Free Slot (usually Spell Shield for Wizard Duels, but Cloudkill is always a highly effective spell)

6th level
True Sight (this will help in SO many situations)
Tenser's Transformation (go to town with the Staff of Rynn or Magi)
Mislead (this spell is an excellent diversionary tactic)
Death Fog (persistent Death Spell, guaranteed 8 hp per round damage, and makes a good replacement for Cloudkill if you don't have it or even combined WITH Cloudkill)
Free Slot (good choices include Invisible Stalker, and any Elemental Summons)

7th level
Mordenkainen's Sword (arguably the best summon in the game)
Ruby Ray of Reversal (replaces Secret Word, hope you waited)
Summon Hakeashar (better than Nishruu, and this will basically incapacitate ANY spellcaster)
2 Free Slots (lot of room here, Finger of Death, Any Summons, Prismatic Spray are all good choices, never personally tried Sphere of Chaos but looks good on paper)

8th level
Spell Trigger (this REALLY increases your power)
Simulacrum (no Vhailor's Helm...)
Abi-Dalzim's Horrid Wilting (excellent damage, no cap, and is just plain cool)
Free Slot (good choices are Symbol:Stun, Pierce Shield, Power Word:Blind)

9th level
Chain Contingency (abolutely devastating...)
Time Stop (very munchkin)
Gate (hehe...)
Free Slot (good choices are Wish and Spellstrike, Wail of the Banshee depends on a save and many monsters at the point where you acquire 9th level spells will make their saves even with Greater Malison)

This is a Summons-Heavy build, which is good for soloing. I tried to include a good number of free slots for variability, and you can obviously choose whichever spell you want out of these lists depending on your situation (i.e. get Breach and Ruby Ray if you are getting pounded by immune Spellcasters...). Comments are welcomed!

P.S. Remember, as a Sorcerer, you can still read spells from scrolls, so only pick those you KNOW you will use frequently, so a spell like Limited Wish is only useful for a few things (a specific quest, etc.), and you can usually acquire 2 to 3 scrolls during SoA.