Having rediscovered stumbleupon since I quit playing my online cowboy game I have to share two new-to-me discoveries (plus one I've known about for awhile) with everybody I know who has a computer:
Stereomood and
AUPEO! Both are free ways to listen to and discover new music.
With stereomood you can choose from dozens of moods or activities and be served up a playlist to match.
With aupeo you can choose an artist channel and be served up that artist plus a few other similar ones you might like (similar to
lastfm)
And of course you know about
Musicovery, right? There you choose a point on a grid: dark to bright on one axis and calm to energetic on the other. You can also exclude certain types of music. You can also ban songs from ever again appearing on your playlists and "heart" the ones you really like.
Don't want music? How about the sound of a gentle rain?
RainyMood.