Interesting Wired interview with a guy who studies music's effect on the brain. He's found, among other things, that music activates the same parts of the brain and the same brain chemical mix as things like having an orgasm, eating chocolate and winning a big poker hand.
Heck, I could have told him that. Happens every time I put on "Root Down: Jimmy Smith Live!" from Verve and listen to Jimmy Smith play "Root Down (and Get It)."