Direct Connect has the most content but no multisource downloads.
http://www.neo-modus.com/
Open source DC++
http://sourceforge.net/projects/dcplusplus/
Since it combines eDonkey and Gnutella 1+2 and Bittorrent it's pretty useful.
http://www.shareaza.com/
Speaking of Bittorrent here are the official programs.
http://torrentlinks.com/