[WinMX was discontinued in 2007] WinMX is quite a nice file-sharing app. It hasn't had any major upgrade in over 2 years but still a pretty good program once you get used to the interface and the queuing system.
A good Gnutella client that is open source and spyware-clean.
Morpheous has had its day - a few years ago it was great. I havn't used it since the Preview Edition got released. We heard that version 2 is not worth using due to the large amount of bundled spyware.
With so many reasons not to use this. Read our page about spyware installed with Kazaa for information about the Spyware problems within Kazaa. If you need to use Kazaa that much you can always search for Kazaa lite - which contains no spyware.
The official BitTorrent client from the developer of the BitTorrent protocol. I havn't used this in a while,It's simple client for a great idea, There are more advanced clients programs though, see below.
A great bittorrent client made in Java. Version 3 looks terrible though, get ver 2.x if you can.
Useful for finding those hard to find files as you can go to the most relevent hub. Don't use this unless your sharing at least 5Gb, as you won't even be allow in most Hubs. Having 20Gb or even 50Gb+ will give you much greater access. This file sharing application doesn't come budled with any spyware.
Don't particularly like this that much, like many others it uses the Gnutella network, seems to be too slow. Also contains spyware - but still works when you get rid of it using Ad-aware.