I definately reccomend the Arcane Trickster. They have an excellent blend of caster levels and rogue abilities. And since you like ranged touch attack spells, you will love the fact that you can sneak attack with them.
For feats I recommend Point Blank Shot, Precise Shot, Weapon Focus (Ray and Energy Missile), Spell Specialization (Ray and Energy Missile), and Arcane Preparation. The latter three are in Tome and Blood, and I believe Arcane Preparation is in FR as well. I reccomend Arcane Preparation because it is the only way a Sorcerer can Quicken, and now that Haste has been changed, it is the only way you can use True Strike in the same round as your touch attack spells. Having some Quickened attack spells is also a nice way to surprise your opponents in battle. The usual metamagics (Empower, Highten, Extend, etc) are also useful. You may also want to get the Reach Spell metamagic, as it gives you alot more ranged touch attack options.
For spells I recommend picking up all of the 0th level "ray" spells (ray of frost, electric jolt, etc). These spells may seem very weak at 1d3 damage, but when you can use them to deal sneak attacks as a touch attack, that changes their outlook entirely! Be sure to get at least 3 of these with different elements (if not all of them), since when you sneak attack with a spell the extra damage is the same type as the spell. Spells such as Shocking Grasp, Melf's Acid Arrow, Flame Arrow, etc are also good picks for your character. But don't forget to take some of support and utility spells as well. Improved Invisibility is a must, since you will want to sneak attack as much as possible.
Hope that helps.