Well, this one doesn't have many known music (at least for me), but it's very good and lets you choose which music you want and also download it for free. http://www.unsignedbandweb.com/
There's a desktop gadget for Windows 7 (maybe works with Vista too?) on Microsoft's website.
Well, there are so many styles of music in there that I can say it has ALL music styles
I dont usually listen to emotional music (or something).
But, when i saw the video "Live For Speed - Still Alive" then now i cant stop listening to this song. Its just so good I mean, usually i dont listen to this kind of music at all. Drum & Bass darkstep/jungle all the time.
If you can listen to these songs, and not want to bounce around like a crazy nutcase (and even think about cutting a hole in your bedroom sheets to make a robe......I know I have) then YOU HAVE NO SOUL.