Have you tried Abilify? It worked pretty well for my aggression and agitation. It, or some interaction between it and my other meds screwed my sleep, though.
The side effects from Thorazine you're thinking of are probably EPS (extrapyramidal side effects), which Thorazine has relatively few of, especially in low doses. What thorazine does have are anticholinergic side effects, so basically like taking a dose or two of benadryl. It also carries the risk of a few of the more major side effects, Tarditive Diskinesia for one, but the major effects don't usually show up until you get into higher doses.
Talk with your doctor no matter what sounds best.
ETA: Forgot to mention that Abilify's super expensive if you don't have insurance that'll cover it. Thorazine's dirt cheap.