You have quite a choice of clients for Windows

LimeWire Pirate Edition

Phex

FrostWire

BearShare

Morpheus

Shareaza

Which client people think is best depends on whether they like the interface, ease of use, options etc.

I've never used Morpheus or Shareaza but have used LimeWire, BearShare & FrostWire. I currently use File_Girl71's release of LW Pirate Edition