I would say in the last third of the round depending on what RBs are available if people reach for some players very good RBs could be available in the back end of round 1.
12 team QBs Roethlisberger, Kapernik RBs Doug Martin, D Thomas, Bryce Brown WRs C Johnson, Demaryius Thomas, Garcon TE Gates K Vinatiari DST Jets, Cards
I am taking a RB if I pick #1-#6 (Foster, AP, CJ2K, Charles, Rice and McCoy) after that I have no problem taking WR or QB if they are best available. Round 1 has to be a player you are very confident will perform well. Those are the only RB's I am very confident about.
Elite WR anytime after #6, but I wouldn't reach for a QB 1st or 2nd round, there's far too much depth at that position.
The only reason I'd be picking up a QB in the first round (ie. Vick) is if a) I had a good backup QB in case of the inevitable injury and b) had every intention of trading Vick mid-season (assuming he's still healthy) to someone crazy enough to think he can maintain that level of play for an entire season. Despite how he did last year, Vick is not a video game.