The Best Recommendations....
I love the suggestions... I categorized them into several groups: the ones I already have on CD or mp3, the ones I have on another medium, those I would like to have, and those I don't know.
I realized that one unspoken criteria I had was that it had to be something I wouldn't go out and buy the whole "album" (yes, I said album - you got a problem with that?), and it had to be something I knew I'd like. For example, I've heard good things about MuteMath, but I've never actually heard them and I'm naturally skeptical about new music.
After some thinking on the great comments (Bryan, I think we're going to have to share music libraries when we get together - legally, of course), I think I'm going to go with "Brick House" by the Commodores (why didn't I think of that one earlier?) and "Mama Said Knock You Out" by LL Cool J - I had actually been thinking about LL Cool J as it was, and the comment just solidified it for me. If I had another song to download, it probably would have been by Run DMC.