When I was in high school, my math teacher would play Mozart during tests, claiming it would help us. It would drive me crazy, and I doubt that my grades improved as a result of the distraction.
For what it's worth, I have a BMus in Piano Performance. I love music... but never as "background noise"!
I love scuba diving. If there was a monitor with rotating images of underwater scenes, I wouldn’t just think it was pretty. I’d be glued to it figuring out where they took the shot, wondering how deep they were and wishing I was there. I’m guessing something similar happens with you and music.
I'm not a huge music-theory guy or anything, but it's virtually impossible for me to "tune out" music; I think I subconsciously like to dissect it a bit.
However, if someone were to put on virtually any sporting event on the TV (without announcers and assuming you didn't have a bunch of people cheering or anything like that), it would have almost no affect on me, since I don't really care at all about sports.
That said, at the same time I pretty much have to listen to music while working, otherwise my brain is like 1/2 as functional. No clue why.