Using my computer's current projections the AFC teams are Indianaplis, San Diego, New England, Cincinnati, Baltimore, and Denver, and in the NFC they are New Orleans, Minnesota, Philadelphia, Arizona, Green Bay, and Dallas. By going through all the permutations of who could meet who, the chance of each scenario occurring, and the chance a team wins the various games, my computer can calculate the chance that any given team gets to the Superbowl and also wins it.
With that as a lead in, let's just get to the results. From the table below, using the week 15 ratings, it is no surprise Indianapolis and New Orleans are odds on favorites to get to the Superbowl, both at over a 50% chance. As the Saints are rated slightly higher presently, they have a slightly better chance at getting there (57.5% to 54.2%) but interestingly the Colts have a better chance of winning the Superbowl. This is because the rest of the NFC is a bit weaker in general than the AFC and the rest of those teams do have a 45.8% and 42.5% chance of being the opponent so that factors in.
It also isn't a surprise that the other division winners that would have home field advantage are the next 4. Those teams that have to go on the road the first week have a pretty slim chance of getting to the Superbowl let alone winning it.
For what it's worth, last year at the end of the regular season Tennessee and Pittsburgh were virtually tied at 19.7% and 19.4% chance of winning and Arizona had only a 6% chance of even getting to the big game. It is interesting that that is right about where Arizona is again this year!
I'll update these next week and then again at the end of the regular season.