I play a Kobold Sorceror (8th level) now under 3.0 + house rules (most charisma based skills are class skill, including Use Magic Device, and I get 4 base skill points. But spells and so are the same)
When I choose spells, I made sure that I had a damage dealing spell on nearly every level, and that (in the long run at least) I have access to every kind of energy. (Magic Missile for force - which is probably no kind of energy, but who cares? - Melfs Acid Arrow for Acid, Fireball for fire, sonic orb for sonic, cone of cold is on my list for cold, and prismatic spray for anything that might be missing

).
Then I took some defensive spells:
Then I took Cat`s Grace (good for my ranged touch attack and Armor Class), Expeditious retreat (Kobolds need it, in case of emergencies), Mage Armor and Shield. (Probably one or two spells are missing in this list).
The next are utility spells:
Haste: It will be useful either in 3 or in 3.5 - in 3 I have the problem I do not always want to waste my precious spells (a sorceror doesn´t have that much more spells per day than a specialist wizard - probably 2 per spell level), but sometimes an ally might need it - in this case, the 3.5 version is superior, since every ally gains his benefits from it.
Detect Thoughts (since Sense Motive isn`t a class skill for my sorceror).
I consider Alter Self (maybe someone doesn`t trust Kobolds? And water breathing or cheap flying might be a good idea), especially since I do not want to learn Polymorph Self/Other.
I will learn fly and Arcane Sight (Tome & Blood, I believe). Fly is always useful, and Arcane Sight allows me to see magical auras without concentrating, so I can instantly see invisible creatures (I know, See Invisibility would be a good alternative, but seeing magic auras gives some other benefits)
My general advice:
First, look for damage dealing spells on each spell level, if possible. In most combats, you have no other way in contributing.
Second, look for good defensive spells, not neccesarily at each spell level, but you should have some basic ones. (Mage Armor, Shield is the obvious choice. Protection from Arrows, Wall of Force and so on might also be useful)
Third, use spells that fit your theme, or spells that have multiple purpose (like Alter Self/Polymorph, Shadow spells, perhaps even Prismatic Spray/wall, but also Charm Person/Monster, Dominate and so on)
For Summoning spells: The lower level ones are mostly useless at high levels. Check if you can find a level that grants you access to a monster that has spellike abilities or spells that you don`t have (maybe healing spells, like the unicorn). (If you summon 6 (?) Formian Workers, you can get a Heal Spell...)
Mustrum Ridcully