iMesh works well, but I had a few problems with them a while back (don't remember what) ... but eventually I 'upgraded' to limewire. If you're paranoid about spyware, I totally feel that limewire's worth the 8 bucks (7.50 or something like that) that they ask for (donation). Upgrading to the paid version gets rid of all ads and spyware, and I hope to do that soon (when I get my new desktop).
I've also heard pretty good comments on bearshare, but have not used it myself.
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