In honor of Stephen Colbert, I am choosing "Eye of the Tiger," by Survivor. Is also v. good for running I've found. In the words of Ron Burgundy:
"I've often said the band survivor is the best that ever was. In my opinion they put rock music to bed. Everyone else is an imitator. That's right, you heard me Beatles, Rolling Stones, Bach, Beethoven, you guys suck...dong."