I like Pandora. Lately though I have been spending more time with the recently added auto-mix feature on my Urge subscription. You can have it pull up a playlist based on your listening habits, mood, an artist, very detailed sub-niches or any song, then then tweak the playlist even further if desired.
I throw a couple playlists along with radio shows from the last day or so on my player whenever I am going to have to be waiting somewhere, turns even the most annoying places enjoyable
