For me, it's pretty much always Alabama vs Auburn; but when the game times don't overlap too much - and when both parts of the rivalries are having decent seasons - I also like to watch Florida-Florida St., Ole Miss-Mississippi St., South Carolina-Clemson, LSU-Texas A&M, and Ohio St.-Michigan. Occasionally there might be a Pac-12 showdown worth watching, too, like Washington-Washington St. I'd tune in for Bedlam, too, when it was the last game of the season, but the Big 12 has messed up the scheduling process in recent years by rotating too many of the traditional end-of-season games.