IME, I play wizards and psions, but never sorcerers. I'm a big fan of saved-or-screwed spells. It it does a little damage, too, great!
The last time I played a wizard, I was a gnome wizard who liked using
glitterdust. However, the party wouldn't stay away, and I wouldn't blind them.
One time the monk, rogue and I conspired to show the party how useful the spell was. We ran into three trolls, so we sent the monk up first. All the trolls went after him (they couldn't see the rest of us yet), putting them all into fireball position. Ok, so they hit the monk 9 times + 3 rends (amazing he was still alive after that!) after which I roasted and then blinded them. Then the rogue started going crazy with sneak attack!
Next combat the fighter immediately rushed into melee... Fortunately I became high enough level to cast Fear and O's Resilient Sphere, but having to wait until 7th-level because of uncooperative PCs isn't really fair.
I found wizards with their d4 hp/level and all-or-nothing defenses to be, well, often annoying to play. If you don't get surprised you're invincible, but if you are suprised, goodbye! (Watch out for elder xorns! They are not CR 8! Not by a long shot!)
Anyway I didn't find spell selection to be a problem. I wouldn't prepare fireballs because I know we'll face trolls; I always had a fireball prepared. Just one though, I also had a lightning bolt. There's a reason I didn't play sorcerers. Having only fireballs when you run into fire giants is a sucky situation. (As for psions, if the GM nerfed the energy powers so they weren't so flexible I'd still take them. I'd just take some of them more than once.

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Now, if you are only planning on casting Identify, that's no excuse for not having a combat spell on hand. Every day a wizard should have prepared the following (depending on caster level, of course): Mage Armor, False Life, Glitterdust, O's Resilient Sphere, Dimension Door.
The last is a real life saver, and Glitterdust and Otiluke's Resilient Sphere take care of a lot of pesky anti-magical creatures. You'll notice these are all defensive spells, too. Offensive spells are more varied and usually reflect your personality or even what you feel like that day. (If you're going to cast Identify after Identify after Identify you probably won't want to bother with Lightning Bolt.)
I think most campaigns start at 1st level. IME wizards and clerics are worth playing until 3rd level. Until you reach that point, you're still an apprentice and shouldn't be adventuring.