Yeah, and I'll make a warlock. Well, I will if I can get in to the setting that is...

What kind of world are we creating these magic users in? And what sort of kingdom/country/whatever within that world? Is magic frowned upon? Or are magic users privileged members of the upper classes? Or does that differ, depending upon the specialization? Are humans the only (playable) race? 

Edit:

Also, can different types work together to create special combinations of magic? Like, could an Enchanter and a Necromancer work together to create weapons that harm ghosts or a sarcophagus that turns any corpse placed inside of it into a zombie/vampire/etc.?