Recommend me a *legal* music download site

We got our daughter an mp3 player for Christmas. It’s a Toshiba, and is a 10 Mg. That means she can download and carry around just about as much music as anyone could possibly want.

The time will probably come when we want to switch from a flat-rate site to a pay-per-song site, but for now, she’s going to want to download lots of songs. So recommend me a good, flat-rate, legal site. If it’s a site you use, please tell me what you like about it particularly. Tell me if there’s something about it you don’t like, and tell me if you tried one but quit because you didn’t like it.

Thanks, Dopers!

I use and recommend Napster To Go. Great selection, decent software.

The Hype Machine, which aggregates free and legal mp3s from free and legal mp3 blogs.