Have you heard of Songza? I recently discovered this website (they also have an iPhone app) and it's pretty amazing. Basically it knows what day/time it is and recommends playlists for you based on what you might be doing. Monday night? Maybe you need an instrumental playlist with no lyrics to help you study? Friday night? Maybe you need an update dance playlist? You can also search by "popular playlists", artist name, etc. I mainly use it for when I'm studying, for background lyric-less music, but you can also find many Pandora-like playlists on here as well. Anyway, I've been meaning to give a shout-out to this app for awhile, so hope you find it useful!