Did a little homework on rivalries in the current century (2000-2009).
Best on-the-field rivalry: Florida State vs Miami The only major rivalry to average less than a 10 point spreat and still yield at least one BCS championship is FSU-Miami (average spread over this period is 6.22 pts per game). Although Miami has an upper hand in wins/losses at 7-3, the closeness of the games and national title implications (past few years excepted) make this rivalry (in my opinion) the best on-field rivalry. This is also the only rivalry to produce a same-season rematch in a bowl game (2003) during this period.
Best championship rivalry: Florida vs LSU No one can contest the success these teams have had this decade. Four BCS titles between them, and though the average point spread when they meet is a lofty 17.56 per game they have nearly split their series at 5-4 since 2000.
Best rivalry for drama: Ohio State vs Michigan Though the Buckeyes have won 7 meetings since the millenia, the average point spread for these games is a mere 11.78. Take away last years 35 point debacle and it's 8.87. Lump these close matchups together with one BCS title and a TON of people watching and you've got a classic year in, year out.
Best rivalry for homers: Oregon vs Oregon State With the exception of the past two years, these teams have taken turns pounding each other at home to the tune of 17.44 points per game. That makes for a lot of happy alumni.
Best rivalry to leave at halftime: Kansas vs Kansas State This one's not even close. The average massacre in this series is 26.78 points, but the series is close at 5-4. Might as well head for the exits after the first half ends.
Best rivalry for no national title implications and one-team dominance: Army vs Navy Seriously, since 2000 no rivalry has been more lopsided than this one. Navy holds an 8-1 edge to the tune of 23.78 points per game. Players rarely go on to NFL careers. And both teams tend to run antiquated option offenses. So why do we watch? We're Americans! We're proud that these guys play hard with no pro future in their sights. We're proud that they wear unit patches on their uniforms in tribute to those in harm's way. And we're proud that at the end of each game both teams stand in silent tribute to the other's alma mater.
Best rivalry for a state fair: Oklahoma vs Texas This one gets a ton of hype, but this decades statistics don't lie. Although it's produced two BCS championships, Oklahoma has taken 6 of 9 and the beatings haven't been close. With the exception of a 7 point spread in 2007 there has not been a spread in single digits. The average for this high-visibility rivalry? 22.56 points per game.
Best rivalry for "We hate the BCS" talk: BYU vs Utah The "Holy War" doesn't dissapoint. An even record of 5-4 with an average spread of 10.11 (second only to FSU-UM). And the winner gets to look from the outside in at a National Championship. Take it from me...when I did "Hate Bowl 2008" this year one thing was apparent. Utah fans HATE BYU. BYU fans generally wonder why they are so hated. If this rivalry had the fire that Clemson-South Carolina has it would get huge ratings.
Oh, and just so I don't piss off my Irish relatives...
Best rivalry for false "throw the records out the window" talk: Southern Cal vs Notre Dame Really. This one used to mean something, what with those gold helmets and that marching band in skirts. Now it's just another excuse to get the Trojans on national TV. USC holds a 7-2 upper hand with an average spread of 24.11 points per game. Sure, USC has ponied up two BCS championships, but did I ever think that I'd see Notre Dame pull a PAC-10 team's strength of schedule DOWN? No. But that's where this one is now.