Favre is going to hurt you. There is just no way he's going to be able to play a full year coming off surgery at his age. I'd be surprised if he didn't come back because he loves the game too much and the Vikings are basically begging him to. But a full season, it's just not going to happen.
Keep an eye out for some sleeper QBs... Alex Smith, Kolb, Young are all poised for a decent year and aren't being drafted much.
Loving your receivers, not so much your RBs... Michael Bush is the most talented RB in Oakland but he's physically doomed to the scatback role which means he's worth it in a PPR but not of much value in non PPR. I'm not convinced Matthews is going to be as good as everyone says he will be. He's definitely not the best back to come out of the draft in terms of skills but just because he's taking over for Tomlinson, he's supposed to be amazing? No, SD is falling apart at the seams.
Forsett is a dark horse though. He's the best RB in Seattle and now there's finally a coach there who can judge talent. And reports from Giants camp are saying Bradshaw is beating Jacobs out for carries. Jacobs will still get goal line of course. If this were PPR I'd say shop Matthews for a better option. Since it's not, Forsett and Bradshaw are solid sleeper options to spell his risk.
Oh and V.Davis is going to be a machine at TE.
Overall, you need another QB. I wouldn't shop trades with a WR because you have nothing behind them. Hester and Jacoby are deep grabs. Your main three are solid though. RB depth looks good even with possible risk, I'd shop something there.