Where do you guys get your MP3s from?

Lisa wants to download some songs, but I'm always leary of sites I've never heard of before.

Primarily she's looking for newer pop/rock stuff, of good quality (wherever she was downloading from apparently didn't have great audio quality)... and without requiring a software download to get them.

Ideas? I was supposed to post a link to the new site she found that looked too good to be true, but I've forgotten the URL.

Bren R.