Great deal if Sheets and Peavy stay healthy enough to pitch effectively. Unfortunately you may end up with two DL's before it's over. Not posting this to criticize either...I would have done the same thing in your shoes and I even have Sheets and Peavy both on one of my teams (traded for Sheets and picked up Peavy as a FA in that one). It's a pitching staff that will make you sweat. :(
Actually I'm in the same boat as you. I didnt' draft either of them but did the opposite of what you did. I picked up Sheets as an FA when a friend of mine was stupid and dropped him. Peavy I just dealt for. If Peavy comes back strong in the 2nd half (from everything I'm hearing, he's getting his mechanical issues fixed) then he easily outweighs having Cliff Lee & Felix. As for Sheets, I don't think they would have brought him back unless he was definetly ok....it would be to much of a risk to their future and they already have him locked in on a deal. I'm confident in both of them.