At this point, it's looking like there are three legitimate contenders to get to the BCS National Championship game: The Oregon Ducks, Oregon State Beavers, and the USC Trojans.
Samuel Chi of BCS Guru files his projections at SB Nation in preparation for the release of the first BCS rankings. The Oregon Ducks are predictably No. 2. They haven't really beaten anyone yet, and they're always in danger of falling back until they start knocking off some quality opponents. The second half of their schedule is backloaded though, so they should start lodging nice wins soon enough.
The Oregon St. Beavers don't have to worry about resume at any point. They're currently 9th, and they're only poised to rise further with any subsequent victories. They still have tough games left, particularly against Arizona State, Stanford, and Oregon, so you figure if they can run the table.
The USC Trojans are just as alive as the Oregons, and they'll have a great chance to land quality victories to catapult them as the top one-loss candidate for a BCS title bid. Beat Oregon. Beat Notre Dame. Beat Arizona State. Beat UCLA. Win the Pac-12 championship. That's a sound 12-1 season if they can get it, and a definite BCS title contender. (even an 11-2/10-2 USC team would be hard to ignore as an at-large)
Plenty of teams are still alive for the BCS, but in terms of actual title contenders, these appear to be the three.