Herrick's from the UK version of Being Human, I haven't seen the US one either. He just appears to be your average bloke, nothing remarkable, yet he's the arrogant head vampire with a Napoleon complex...even if he is dumb for locking himself in a room with a werewolf. I think you're right about Bilis...I think because we don't really learn about his motives or what he is exactly that it really ups the creepiness factor in him. He appears such a nice, elderly gentleman and so isn't.

I'm catching up on S2 of Being Human (UK) atm and the Big Bad in that might find his way on this list. Ooooh, not a nice man at all!