Apollon
Is a KDE-based client for the p2p-protocol giFT (OpenFT, FastTrack(Kazaa!),..) It is very userfriendly, intuitively, offers an inline Mediaplayer for previews of downloaded files, etc etc.
(btw, anyone tryed yet?)
Screenshots:
http://apollon.sourceforge.net/apollon1.png
http://apollon.sourceforge.net/apollon2.png
http://apollon.sourceforge.net/apollon3.png
http://apollon.sourceforge.net/apollon4.png
http://apollon.sourceforge.net/apollon5.png