My friend, Timmy, turned me on to www.pandora.com, and I am hooked. You can select a song or an artist, and the website will build a radio station just for you. As new songs play, you can keep or discard them. Ultimately, you make a playlist of the exact sort of music you want to listen to. Dance, chill, 80's, rock... whatever you are in the mood for, you can have it at your fingertips.
And, I can add my list of radio stations to my blog. Check the link out in the sidebar. This rocks.