When I was a kid I was a big fan of WWF wrestling, and part of the deal with a wrestler's personality was what music was played when he walked to the ring. My favorite wrestler, Macho Man, came to the ring to Pomp and Circumstance. Junk Yard Dog came to the ring to Queen's "Another One Bites The Dust." That is, until, WWF created The Wrestling Album. After that he came to the ring to Grab Them Cakes. That's also around the time Hulk Hogan picked up on "Real American" by the legendary Derringer.
My reason for this tangent is to put some perspective on the topic of music for baseball players, which I hadn't given a whole lot of thought to until last year's "controversy" with Billy Wagner and Metallica, though I do remember being annoyed when John Franco gave up on "Johnny B. Goode" in favor of "Boy From New York City". During Spring Training this year, David Wright let MLB.com voters choose the music played when he comes to the plate this season (Blame MetsGrrl for that one). Meanwhile, Jose Reyes composes some of his own entrance music.
Over in the comments section of Metsblog, MouserDZ posted a link to a website that lists a bunch of MLB players and the song played when they come to bat or are introduced into the game as a pitcher. Have a gander if you're interested. The only thing I really found interesting is that according to the site Armando Benitez has finally gotten over "Who Let The Dogs Out" and has moved on to "Big Pimpin'" and "Big Poppa"
So there you go.