Only seems to be BW's really, which is a bit restrictive, at least WoW had Mage (fire, arcane or frost), Warlocks (fire, shadow, or demo) or shadowpriests.
That's a pretty decent choice - I'd like a caster dps as alt, but really don't want to play BW (too many around). Is there any word on getting a new one, or will the hammerer/slayer be the last class we'll get?