There's a lot of online radio resources out there.... probably too many.
One I've recently played with is the Pandora service. You enter a band or song that you want to seed your listening on and it will customize a made-to-order station. The best part is you can thumbs up or down individual songs that Pandora matches to your musical profile. The more feedback you give, the better it works. And it's put me on to some new artists I was not aware of. The 'music genome' as it's called is not perfect, but I think Pandora is as good as it gets for radio listening over playlist listening.
