NBA: Bulls (Was a huge Jordan fan, gave up on the Bullets when they abandoned their name for the failure that is their current name)
NFL: Skins (Ravens didn't exist when I became a football fan)
MLB: Orioles (Nationals didn't exist when I became a baseball fan, don't really watch baseball anymore either way)
NHL: Caps
NCAA: Maryland (undergrad and MBA), to a lesser extent UConn (law school)
Unless you're a Ravens fan, being a Maryland/DC area sports fan has been painful for just about as long as I can remember