Spotify
Spotify is a proprietary peer-to-peer streaming music program that allows instant listening to specific tracks or albums with almost no buffering delay. Music can be browsed by artists, albums or created playlists as well as by direct searches.
There are no restrictions in terms of what you can listen to or when. Forget about the hassle of waiting for files to download and fill up your hard drive before you get round to organising them. Spotify is instant, fun and simple.
Because music is social, Spotify allows you to share songs and playlists with friends, and even work together on collaborative playlists, Friday afternoon in the office might never be the same again! We’re music lovers like everyone else.
Users can access around 3.8 million tracks via searching for artists, albums, titles, labels and genres. Spotify features a large and constantly growing library of music, giving users access to tracks from all major labels as well as numerous independent labels.
Users can set up playlists and share them, or edit them together with other users (see collaborative software). For this purpose the playlist link can directly be dragged into an email or an instant messaging window. If the recipient follows the link, the playlist will be downloaded into the Spotify-client of the recipient.
Its basically like having my own huge personal music collection, you have to download and use a client (that kind of reminds me of Songbird). The software is great, all common functions, but the playlists are the key for me, especially the social aspect. I've found lots of great music through downloading other peoples shared playlists.
http://www.spotify.com(Plus hot girl on front page)