Are there any services similar to Pandora (or the Music Genome Project) for download?”
Pandora unfortunately does not yet have a downloadable client engine, but Last.fm is a very similar service that does have a separate program, although it does still require online access, obviously. In my experience Pandora’s recommendations are slightly better, but Last.fm has the advantage of tying into iTunes so that you can rate anything that you’re playing and transition seamlessly into recommended or similar music, or to music that your friends are listening to. It’s an excellent tool, and it sits in your task tray not occupying too many resources, so I typically just leave it running all the time and maximize it when I want to listen to something. Much quicker than navigating to Pandora, even though I love pandora too.