well if your into P2P file sharing a junkie like me has all of'em. I use nothin but the best! I hate spy ware, the origional program u get, lets say kazaa has alot of junk in it and makes your downloads slow plus it limits your downloads because u must participate. I recommend KaZaA Lite +++ cuz its free of spyware.
Also the biggest file sharing network is Direct Connect, they have over 12 Trillabytes i think... and also MiRC is really good too. KaZaA is mostly for newbies but if u want something specific, MiRC is it...