There are three kinds of basketball fans in the Triangle: Duke fans, Carolina fans, and State fans, i.e. "fans who hope that the Dean Dome and/or Cameron will suffer a fortuitous meteor strike when Duke and Carolina get together". This is due in part to the relentless overexposure the rivalry gets, and in part to the fact that 98% of the carpetbaggers who move down here immediately become Duke fans because, hey, nobody in the Northeast can play college football, either.
(The closest thing I have to a rooting allegiance in college basketball is for the Big Five; I'm happy to see Temple, Penn, Nova, St. Joes or LaSalle take down anyone.)
Duke-Carolina really is the Yankees-Red Sox of college hoops: a stirring rivalry that has been relentlessly hyped and sold as the only rivalry in the sport worth paying attention to. What that means is that other, equally interesting teams don't get as much play, weakening the sport as a whole. It also means that when one of the two titans in blue is having a down year - like this year - all the Chicken Littles immediately start going off on how "the rivalry has lost its luster" - and the sport as a whole is diminished as a result.
Duke-Carolina is great. So's 'Nova-Georgetown. And Purdue-Indiana. And Louisville-Kentucky. And any number of other rivalries. Until Dickie V admits that he's actually Connor McLeod's great-grandpappy - which is not out of the realm of possibility - it should be clear: there can be more than one.