I only tried the most popular of the listed ones,
- Napster, (...)
- morpheus/Kazaa/grokster,
- Audiogalaxy, (also used other GUI than the official one, funny but useless most of the time)
- winmx, (never liked it)
- edonkey, (i dont care about divx so i dont like edonkey)
- napigator, (... never managed to dl a song only with napigator
)
- rapigator, (allows using html code on the chatrooms
)
- direct connect, ('cool' communities, easy and funny to launch a new server)
- scour exchange, (which is dead but i liked it)
- cute MX (dont remember if this one is dead... i think yes, the same sort of prog than scour)
- aimster, (launched it a few times, but not a vast choice in MP3 so i stopped using it)
- file navigator, (same as rapigator [without the HTML])
- xolox, (easy to use... the official one is "blocked")
- limewire, (i HATE JAVA)
- imesh, (spywares ! but not so bad...)
- gnotella, (i dont like gnutella network)
- audiognome, (i used it for months and years, i loved it, the best opennap client IMHO)
- Abe's MP3 Finder, (an old one, is it still alive ? remember it was difficult to find something to dl)
- a few opennap clients dled on opennap.sourceforge.net
as i only search MP3 i prefer Audiogalaxy for its choice.
Ever heard about Slavanap ?
Flipr, for sharing legal stuff, too much unstable, the beta-test period is finished and actually flipr is closed, it was cool to discover unpopular artists.
Soulseek, only good for dling electronic music.
Freenet, Espra, interesting project, but not so easy to use