At the moment I'd go with....
Denver
Baltimore
Kansas City
I wouldn't anoint the Broncos just yet, but they show very well in a magnitude of categories previous SB winners seem to excel in (stopping the run, protecting the QB and rushing the passer). The biggest concern for me would be the rushing offense, which has been atrocious. I don't believe a team has ever won a SB with a rushing offense as bad as Denver's currently is, in fact, I don't think a team has ever even made it to the SB with a rushing offense this poor. One dimensional teams tend to falter somewhere along the line in the playoffs. Maybe Hillman is the answer and will help turn things around for them on the ground.
Just my $0.02.