Pandora is the best music-related technology I’ve run into in a long time. Simply put, it’s custom streaming radio based on your musical tastes. Doesn’t sound that revolutionary, but the “Music Genome” project underneath it does a really good job of coming up with new music that fits your tastes, based on seed artists and songs you provide it. And it’s recommendations aren’t based on what a record label is pushing, or what era it’s from, or how many other people bought it. Also, it’s free.