I know national media people would argue that Duke-North Carolina, or Pats-Colts, or Lakers-Celtics.
I'm provincial. My two favorite rivalries are Packers-Vikings, and Twins-White Sox.
Nothing matches the sheer intensity and incestuous anxiousness surrounding Packers-Vikings, especially following Brett Favre's grand betrayal.
But for a baseball fan who values the game's constant presence during the course of the summer, I'll take Twins-White Sox. In part because I know just how angry the White Sox get when the Twins beat them.
It's pretty funny, actually. I've had sources tell me that White Sox GM Kenny Williams used to sit in the Metrodome dugout, look up at the Twins' banners, and loudly and profanely ask how a bunch of bunters like the Twins could keep beating his stars.
You've got the friendly competitiveness between Gardenhire and Ozzie Guillen. You've got Ozzie's nicknames of the Twins' lineup. You've got A.J. Pierzynski trying to spike Justin Morneau, and, of course, putting himself in the middle of every imbroglio between the teams.
You've got Torii Hunter running over a no-name catcher in much the same way Buster Posey had his leg broken this season. And in modern baseball, you have all of these memories evoked 13 times a year.
Packers-Vikings is a great movie you're willing to see twice. Twins-White Sox reflects my favorite pop-culture art form - the serial TV show. It's always there for you.