IMO, I would have to say the Big 12, especially as of late. This past year, the Big 12 had 4 10 win teams, and one team short of 10 wins. Looking at the Pac 10, it is usually a two horse race, with USC winning the battle. Oregon may stay on top for a while, but Stanford is screwed after Luck leaves, and I don't think they'll win 10 games with the majority of their O line leaving this year. USC of course will be back on top. With that said, the Big 12 usually has 4 teams that are competitive (OU, UT, NU, and one of the north teams). Just my lowly opinion though.