4 year old boy with aggression ?

My 4 year old son is too aggressive and has no remorse about it, he hits, kicks and bites everyone if he's angry. He fights us on bed time every night, he just doesn't want to sleep. He has been doing this since he was 1! He is very smart for his age and very imaginative. He is also very manipulative and learned to lie. We've lost baby sitters, and pre schools over his behavior. My wife and I have tried everything, we looked at all the websites and read all the books! We've tried time outs, spankings, taking things away, positive re-enforcement, charts, bed time routines, scare tactics... you name it we've tried it and nothing works for more than a day or two. We even went as far as to take him to the police station to give him a scare and show him what happens if he continues to hit, so far nothing. My wife cries her eyes out over his behavior and it has caused many fights between us. I need some real advice about what to do because I don't want to lose my son and wife over this problem.