NO NO NO
I WILL STAND VIGILANT OVER THIS FORUM
Pandora is NOT the best choice. It is slow, stupid, and not nearly as much features as the best choice. It also crashes my pc after like a half an hour of using it. Fuck that.

No, if you want THE BEST online music radio/taste service/myspace-like-feel (i don't like myspace, but it's a part of the program and it's actually very cool, it's not annoying or customizable or anything, but it's a social program)
Get LASTFM
Go to lastfm.com, download the free software, you just gotta trust me on this one. It's even better if you get your friends on it around the same time, you can see what they're listening to while they're listening to it (even their own music!) and you can... ugh just get it you'll see. I'm only trying to help.