When I think about baseball songs, I always forget about "Joe DiMaggio's Done It Again," with lyrics by Woody Guthrie and everything else by Wilco and Billy Bragg. I forget it because I don't care for it much (even though I adore Wilco). This, on the other hand, is a pretty nifty version, via The Onion's AV Club:
Of course, the current champions of the baseball song are The Baseball Project ... and they'll be at Portland's Doug Fir next Wednesday night! I'll be there, if that makes any difference.