What does your husband say about his behavior? How does he deal with your son?
Probably every parent has a trick he or she thinks is the guiding light of child rearing. Mine is consistency. Behavioral research shows that severity of punishment is ineffectual, that the factors that stand out as most effective in discipline are immediacy and consistency. These factors are especially important with very young children, who haven't much interest in what happened a minute or five minutes ago.
What does this mean in the family? It means that you catch him RIGHT AWAY, EVERY TIME. The point where discipline fails in most families is that parents are busy, they can't give that kind of attention to watching the children closely, and discipline is delayed. To make it worse, a parent becomes frustrated and is likely to punish the child more severely, even angrily, which makes it worse.
If you want to kick-start some behavioral change in your child, all the adults in the household can agree to what behavior occurs at lot that they want changed. At first, someone can be watching your son at all times--punishing him later is just about useless. As soon as he starts the behavior you have decided to change, that person performs the agreed discipline--seating him unceremoniously in a chair where he doesn't want to be will work. It isn't necessary or helpful to make him stay more than a couple of minutes (there are charts of how long a time out is best for each age) and becoming angry is counterproductive--the point is that the behavior is caught immediately and punished EVERY time.
It's pretty labor intensive at first. You can't change all the behaviors at once, and you have to concentrate whenever he is awake. But more behaviors change faster, and you become less frustrated with experience.
Good luck.