Way up on north end of town is the All American Sports Cafe. They've six TVs in the bar area, and some really good pub food. We're they're on a regular basis. Voyager Pkwy and Middle Creek Drive, about 1.5 miles north of the intersection of Interquest Pkwy and Hwy 83; just off I-25 exit 153 (Interquest). Not noted for Bills fans, but the folks there will tune in any game you wish.
I might suggest calling some of the Old Chicago locations around town, you might find one that has a Bills crowd.
The Bills are out here to play Denver on 12/21/08. Tix to the game are available at:
DenverBroncos.com :: Official Web Site of the Denver Broncos
I'm from the DC area, couldn't get Redskin tix unless I mortgaged the house. Came here and saw the Redskins play in Denver, via the Bronco's half price deal. Parking at the stadium is $40/car, best to take the bus from here.