I'm looking for music player, that would be able to do that:

Download covers.
Download music automatically via torrent, basing on what i'm listening and similar artists from last.fm
After downloading, tag downloaded music and move it to folder with music.
Autmatically add new music to "new music playlist"
Sort music by quality, and automatically compress music with too high quality to level i choosed.
And i want to be able to easly manage my huge music library.

So it's music brain picard + torrent client + music compressor + music player, that works automatically.

Amarok is the closest on what you'd like to do, VLC is pretty advanced too.

try Winamp if you're on windows