I think my definition of most-rivaled would be the team I most want to stick it to when we play them. So you're talking the over-all most rivaled, and not my own most rivaled, is that right? I think it can change from year to year, also. So, as of now, I would say I think it's:
1. Cowboys
2. Patriots
3. USC Trojans
4. Yankees
5. Lakers
If you asked Rex Ryan, I'd imagine he'd say the Jets are at the top of the list. I think there is a direct correlation between how highly a team and a fanbase think of themselves and how intensely other teams and fanbases feel about the rivalry. 5 or 6 years ago, I'd say the Yankees are close to the top, but not so much right now. A few years ago the Patriots would've probably been #1. Honorable mention goes to Dale Earnhardt Jr.