Since I set up a wireless network at home, I'm connected to the Internet all day long. One benefit to this is that I no longer need to depend on my own music collection for entertainment, or listen to ad-intensive radio. My favorite alternative these days is Pandora.
Pandora.com provides me an endless stream of music customized to my tastes, for free. It has a very interesting method of matching music to my tastes. The company hires real people, mostly musicians, who listen to music and attempt to categorize it on 400 criteria. This is an outgrowth of founder Tim Westergren's Music Genome Project.
When I log onto Pandora, I can create my own station (or more than one) by choosing a band I like. For example, I have stations for Radiohead, Pink Floyd, Frank Zappa, Charlie Mingus and K.D. Lang. Pandora then feeds me music by the group of my choice, interspersed with other songs/musicians that share points of commonality. I can fine tune the match by voting up or down on each song fed. I've found this a great way to find new artists that appeal to me.
Pandora is advertising-supported, but the ads are visual, not aural, so nothing interrupts the music feed. The service is so cool I fear it won't last, but for the moment, I'm groovin' on my free tunes.