SRV or hendrix is are good ideas. also maybe check out some clapton (never one of the best singers!) layla might be a good one.
also maybe:

school's out for summer - alice cooper
should i stay or should i go - the clash
i fought the law - the clash
satisfaction - rolling stones

hopefully (depending on how classic rock your audience is) they'll know them and sing along, giving your singer a chance to strut about not needing to sing :D

btw hocus pocus would be brilliant!!!