my current p2p habits....
1) <a href="http://www.mirc.com">irc</a> (specifically undernet; #mp3passion) - the only way to go for prerelease and new full albums.
2) <a href="http://sourceforge.net/projects/gnucleus">gnucleus</a> - my preferred client for 24/7 serving for a variety of reasons and features; but i admit i rarely download with it.
3) <a href="http://download.cnet.com/downloads/0-1896420-100-5590701.html?tag=st.dl.10001-103-1.lst-7-1.5590701">morpheus</a>/<a href="http://www.winmx.com/">winmx</a> - what i have to use right now for back catalogue stuff when i need it; i just don't like winmx and morpheus; it's obvious they are gonna bust out a for profit model sooner or later that will screw the users so i'm not bothering sharing on their systems.
i've taken audiognome, napster, and bearshare off my system for different reasons. i'd love to serve on morpheus but the memory leak kinda nips that in the bud. i'm keeping my ears open for when it's fixed.
many folks love <a href="http://www.forteinc.com/agent/freagent.htm">usenet</a> still for mp3s; i'm not one of them but if your not familiar with it you should give it a try just to know what it's all about.