Giants trade a 5th rounder in 2011 and a 2012 conditional pick for Sage Rosenfels. That is a little rich, but the Giants really had little choice once Sorgi went down. Of Leinart and Rosenfels, the Giants certainly got the better QB. He's a good player, fits with the Giants. This move had to be done because Bomar was not ready. Bomar still needs to be groomed. Show him patience and make him the #3 QB.
In the deal the Vikings threw in a punt/kick returner. This guy was Harvin's backup.
EXTRA: If you had any doubts about Sage Rosenfels as a quality QB and solid pickup, read this opinion from the ESPN Blog. There is no room for ego on your staff. The Giants got Hixon and Hedgecock by profiting from internal squabbles on other teams. Add Rosenfels to that list.