Any team that's an arch-rival to the Yankees, is alright in my book.
Up until 2003, I had viewed the Boston Red Sox as simply another divisional rival of my favorite team, the Baltimore Orioles. However, when the Red Sox and Yankees clashed in the 2003 ALCS, things took a turn and I developed a unique relationship with them. The way I saw it, "the enemy of my enemy, was my friend", which means I had no better friend than the Boston Red Sox during that time period. It was loads of fun to cheer on the Red Sox as they tried to vanquish the "Evil Empire", and it was even more fun to rub each of their victories in the faces of all the Yankees fans at school.
By the time Aaron Boone's home run took flight in that horrific Game 7, I knew that the Red Sox had formed a connection with me that went beyond simply rooting against the Yankees. My heart ached after the game like the Sox were my own team and a unique bond was formed. Ever since that series, I've been keeping a close eye on the Boston Red Sox and rooting for them in their constant quest to defeat the Yankees. While circumstances certainly have changed since 2003, and rooting for the Red Sox to beat the Bronx Bombers is basically cheering for Evil Empire "B" to take down Evil Empire "A", it's still a lot of fun. Face it - watching the Yankees go down in flames against their arch enemy just never gets old!