I'd have to agree with you that your roster is a bit top heavy. That isn't necessarily a bad thing, because you have several studs.
You got great deals on Beanie Wells ($1) and Eli Manning ($1) Wells could produce RB2 numbers if he stays on the field the whole year with the competition injured in Arizona. Eli Manning is a very solid backup for Mike Vick if Vick goes down due to injury.
As far as FA pickups, I definitely think you should scoop up some punt returners. Are Davone Bess and Jacoby Ford available in your league? What kind of free agents are on the wire? How many yards per point do you need on returns?
Good luck in 2011