I play lots of sorcerors. Here's my build, it's fairly optimized.
Stats, in order of importance: Cha, Con, Int, Wis, Dex, Str. I sacrifice Dex and Str because they are completely obsolete once you have Polymorph Other. Con isn't obsolete because of the funky HP calculations with PO.
Race: Human for the extra feat, and to a lesser extent the extra skill point. If you can get a +2 cha race, go for it, but don't pay a level penalty for it.
Feats & prestige classes, in this order. For the plain MotAO:
1) Arcane Preparation, Empower Spell
3) Cooperative Spell
6) Now Sorc5/MotAO1, Feat: Spell penetration
7) Bonus meta feat from MotAO is either quickened spell or energy subs
9) Greater Spell Penetration
12) Spell Focus (Necromancy)
14) Bonus meta from MotAO, your choice.
15) Greater Spell Focus (Necromancy)
Option: Spellcasting Prodigy is good, but it will delay your spellpool access by one level all the way to the end, which is really annoying.
Notes: Spell Penetration is actually useful with a very large number of creatures, especially at level 8+. Spell focus is largely dependent on you taking necromantic spells, my favorites are Wail of the Banshee, Finger of Death and Magic Jar, to share with your familiar.
Spells, with a * next to the crucial ones:
1) Mage Armor, Magic Missile*, Reduce*, Expeditious Retreat, Shield
(You may not need both Mage Armor and Shield. The purpose of reduce is to teleport your friends and/or loot.)
2) Alter Self*, Eagle's Splendor, Cat's Grace, Endurance, See Invisible, Research a 10d6, save for half, single target spell (as per DMG guidelines.)
That's one more spell than you're allowed. Glitterdust is good, but you can't see ethereal with it.
3) Haste*, Protection vs Elements, (Fireball or Lightning bolt or similar), Flame Arrow.
Flame arrow does 20d6 at level 20, or 50d6 when triply empowered. Check to see if your DM will let you upgrade spells later in your character development, you might want to do that with Prot Elts.
4) Improved Invisibility*, Polymorph Other*, Spell Enhancer*
Unfortunately, SE is from Magic of Faerun, sweet-talk your DM or "invent" it.) Adds +2 to the DC of your next spell, cast as a free action.
5) Teleport*, Wall of Force*, Magic Jar, Ghostform.
Magic jar is a necromantic spell. See if you can cast it on your familiar instead of yourself (depends on your reading of "share spell" and Magic Jar.) Failed teleportation is not very risky at all, if the rules are followed properly.
6) Eyebite*, Greater Dispelling
Share eyebite with your familiar for a double whammy. Suck disintegrate from the spellpool when you need it. Eyebite goes through WOF.
7) Finger of Death, all of these are very good: spell turning, power word stun, mordenkainen's sword, energy immunity.
8) *Mind Blank
This is an essential spell. Horrid wilting is funny, but it doesn't do as much damage as lower level empowered spells.
9) The usual suspects. Make sure you somehow get a Hide Life at some point though, preferably from the spellpool.
Elemental savant build is substantially the same. Claim you can cast the required elemental spells from the spellpool, and get your Knowledge: the Planes when you're a MotAO. Depending on your int score, you can qualify fairly early. (I still take MotAO.)
The uber build is of course the Archmage, but it's costly. If you'll be playing mainly below level 15, don't even think about it. If you take spellcasting prodigy _and_ MotAO, the archmage will be at like level 16 or something.