Well, I can't think of a paticular song that changed me, but I can think of a few things that immediately grab my attention and can alter my mood for the rest of the day:

SRV's version of "Little Wing" off of "The Sky is Crying"- Every time I listen to that song I find a new level it works on. I really belive that Stevie was tapping into some greater being or reality. This song moves me 10 times out of 10... you know?

"To Defy the Laws of Tradition" by Primus- I'm a bassist first and formost, and everytime I hear this song (which opens up the album "Frizzle Fry") I feel like I'm hearing something brand new and totally original. When I've been forced to listen to hit radio for an extended period of time this is one of the albums I run to largely because of the transition from the into to the main riff at the beginning of this song.

Morphine's entire "Cure for Pain" album. This whole album is psychological therapy for me. Also, Morphine is my big reminder that I don't have to play monster techniques all the time. They keep me in touch with just how powerful a simple idea can be, and how important it is to inject your feelings into your music.