eMule 0.49c

eMule is one of the biggest and most reliable peer-to-peer file sharing clients around the world. Thanks to it's open source policy many developers are able to contribute to the project, making the network more efficient with each release. eMule is a filesharing client which is based on the eDonkey2000 network, but offers more features than the standard eDonkey client.

A list of a few features available.

Clients use several networks to create one reliable network. (ED2K, Source Exchange, Kad)
Kad is now in an open testphase, eMule v0.42 can be enabled to use Kad
eMule's Queue and Credit system helps to ensure that everyone will get the file he wants by promoting those that upload back to the network.
eMule is completely free. eMule is also completely free of any Adware, Spyware, and ect. We do this for fun and knowledge, not for money.
Each file checked for corruptions while downloading to ensure an error free file.
The eMules Intelligent Corruption Control helps to speed up the correction of corrupted parts.
Auto priorities and Source management allows you to start many downloads without having to monitor them.
The Preview function allows you to look at your Videos and Archives before they are completed. For video previewing, we recommend the Video Lan Client.
The eMule features webservices and a webserver that allows you to have quick access to and from the internet.
You can create categories for your download to organize them.
To find the file you want, eMule offers a wide range of search possibilities which include: Servers (Local, and Global), web based (Jigle, and Filedonkey), and Kad (Still in Alpha).
eMule also allows you to use very complex Boolean searches that make the searches much more flexible.
With the messaging and friend system, you can send messages to other Clients and add them as friends. In your friend list, you can always see if a friend is online.
With the build in IRC client, you can chat with other downloaders and chatters around the globe.