Thanks to my friend Billy Hollis, I appear to have found the radio station I've been looking for: Pandora.

This is an online streaming service with a brain. You tell it some of your favorite artists and/or songs and it assembles a radio station that plays music similar to (and including) your selections. It calls the artists and songs you pick "seeds", and apparently uses some sort of genome-based algorithm to find that similar music.

I've been listening for nearly an hour now, based on my seeds (Rush, Queensryche, Godsmack and Disturbed) and it absolutely rocks!

The only glitch I've found is that if you open it in two browsers, it plays both songs over the top of each other. But that's more a user error than their issue I think

Not since CyberRadio 2000 got squashed by RIAA have I found quite the service I was looking for. I had hoped zune.net would do something like this, but Pandora beat them to it.