I listen to music all the time, it's never caused me to drift into other riders. In fact, I'd say that of all the erratic bicyclists I see on the bike path, very few are listening to music. I've noticed that when I listen to music, I ride farther, when I don't listen to music, I ride faster. The dangers of riding with music have been greatly exaggerated. Deaf people ride bicycles every day and live to tell about it.
When I listen to music, I like 'Zeppelin or some old school 70's rock. I also listen to the "Podrunner" podcast. I have an iPhone so my music fades down when an incoming call comes in, I tap a button on my earbuds and answer the call. Totally hands free. When the call is over, the music fades back up.
I also listen to "audio books" as I ride, mostly I'm learning to speak better Spanish. Sometimes if there's a lot of cyclists, I'll pop out one ear bud so I can hear what's going on. Today I rode 22 miles without music, it's fun to hammer hard and listen to your bike and get into your breathing and really feel the Zen of the whole experience. But other times it's nice to crank some Robin Trower and just pedal mindlessly.
You can even get a TV for your bicycle:
