I'm a big fan of online radio, especially since I hate having to pick my own playlists sometimes. A friend recently pointed out SomeFM to me, and I'm in love. It has a perfect suite of radio stations - as long as you are into techno/trance/ambient/indie/etc. I've been playing Groove Salad and indiepop rocks all week.
Another very cool service is Launch. Imagine a radio station where you can specify that you like classical, jazz, rock, but hate country. As you rate songs, it gradually learns your styles at the same time throwing in random tunes every now and then to help broaden your horizons. I can't recommend it enough. Plus, they also have an amazing library of videos. I've been a Depeche Mode fan for years, but since MTV decided to stop playing videos years ago, I haven't seen many of their videos. For example, I finally got a chance to see Blasphemous Rumours, which was... errr... well, pretty much what I expected for such a depressing song. -grin-
Anyway - why would anyone bother listening to radio anymore? I don't mind the ads (Launch has ads), but half of the time the selection is crap and the other time it's inane radio "personalities" trying to be funny.