Azureus is a Java based BitTorrent client that offers multiple torrent downloads, queuing/priority systems (on torrents and files), start/stop seeding options and instant access to numerous pieces of information about your torrents. It also features an embedded tracker that is easily set up and ready to use.
Download: Azureus v2.3.0.2
View: Changelog
News source: azureus.sourceforge.net