Ars, the choice between these two is a difficult one to make and I like Brady very much he is one hell of a QB, in the end the question of who is the QB of the decade means little except for bragging rights for people like you and me.
I will take exception to one statement you made however. Manning does not win because of the system around him, You cannot just plug in another QB in that team and get the same results. A fact that will no doubt be born out in a few years when he decides to retire. There is no one who studies and understands the game better then he does. There may be QB's out there who actually will have more talent then he has, but not the understanding or the commitment to the game that he has. He makes everyone around him that much better.
Quarterback of the year? Quarterback of the decade? Quarterback of all time? I really don't care about any of that in the end. Come Sunday afternoon, I just know he is the guy I want leading my team.
I would have course been a lot more happy had we won the Super Bowl, but let's not forget....Manning PLAYED IN THE SUPER BOWL.....Brady WATCHED IT ON TV1