Mike Clayton, WR Ravens - I think with an average QB, he will be a great pickup if you get him in the later rounds.
Matt Schuab, QB Falcons - Maybe a pickup after the draft, because if Vick ever goes down (which seems to happen each year), he may be a solid pick.
My pick for RB: Laurence Maroney, Pats - With Dillion looking like he has started the RB decline that is inevitable, I think Maroney will pay off big time.
ANd because I'm feeling gutsy:
Aaron Brooks, Raiders - I'm mixed on this guy. With Moss and Porter, you have to think even if he is an average QB, he'll be fine. However, he struggled with WRs like Horn and Stallworth in New Orleans, so it's very difficult to get a good read on him. So why do I say he is a sleeper? Art Shell. I think Shell will use a system that plays to Brooks strengths.
Finally, I'd also say the QB that wins the job in Buffalo. They have a talented team, and I'd tend to think JP will be better after his learning year last year, KH is a player I always thought could do some damage, and finally Nall is someone who I like, and think he could do some good things if given a chance.