I think the most underrated guy may be Orton. He strikes me as simply intelligent this year.
Sorry- gotta violently disagree with you on this one. Orton has been a huge beneficiary of a) luck and b) "terrible play by opposition defense" so far this year. Case in point:
Week 1- Orton won the game after the second to last ball he threw just missed being intercepted (defenders 2nd foot was barely out of bounds), and after his last throw was perfectly defensed by the secondary but just happen to bounce directly to Brandon Stokeley... it should be noted that none of the Bengals actually chased Stokeley down the field.
Week 4- Orton's pass to Marshall was thrown into coverage and should have been knocked down by Terrence Newman, after which the Cowboys defense was a comedy of errors in trying to tackle the receiver.
I won't argue that you have to get lucky to win in the NFL, but let's not confuse luck with playing intelligently. It also helps when your first 4 games include games against Oakland and Cleveland.
Not to fault the Broncos for their schedule, you still have to win the games, but 7 of the next 9 games are against San Diego (twice), the Ravens, the Steelers, the Pats, the Giants, and the Colts. I think we will truly see how good the Broncos are after that stretch. If you look at the schedule, only 4 of the remaining 12 games look like wins- KC (twice), Washington, and Oakland.