More information: http://deluge-torrent.org/
Deluge is a full-featured BitTorrent client for Linux, OS X, Unix and Windows. It uses libtorrent in its backend and features multiple user-interfaces including: GTK+, web and console. It has been designed using the client server model with a daemon process that handles all the bittorrent activity. The Deluge daemon is able to run on headless machines with the user-interfaces being able to connect remotely from any platform.
Deluge features a rich plugin collection; in fact, most of Deluge's functionality is available in the form of plugins.
Deluge was created with the intention of being lightweight and unobtrusive. It is our belief that downloading shouldn't be the primary task on your computer and therefore shouldn't monopolize system resources.
Deluge is not designed for any one desktop environment and will work just fine in GNOME, KDE, XFCE and others. We do our best to adhere to the freedesktop standards.
Deluge is Free Software and is licensed under the GNU General Public License.
Who made Deluge?
The Deluge Team consists of Andrew Resch, Damien Churchill and John Garland. Previous developers and contributors include Zach Tibbitts, Alon Zakai, Marcos Pinto, Martijn Voncken, Sadrul Habib Chowdhury, Alex Dedul, Ido Abramovich.
The libtorrent library is a huge part of Deluge and is developed by Arvid Norberg.
What about features?
Deluge has a wide-array of features, including:
Core/UI split allowing Deluge to run as a daemon
Connect remotely to the Deluge daemon
BitTorrent Protocol Encryption
Local Peer Discovery (aka LSD)
FAST protocol extension
µTorrent Peer Exchange
UPnP and NAT-PMP
Global and per-torrent speed limits
Configurable bandwidth scheduler
RSS (via Plugin)
Other libtorrent features
And much more!