qBittorrent : a C++ / Qt4 Bittorrent Client
About qBittorrent

The qBittorrent project was created in March 2006 with the idea of developping a new Bittorrent client for Linux (and possibly other systems) that would be easy to use, good looking, featureful but lightweight.
qBittorrent is a Free Software released under the GNU GPL license.
The author is Christophe Dumez, a French student in an engineer school (UTBM), in IT departement.
qBittorrent is based on the great Libtorrent by Arvid Norberg.
qBittorrent features
qBittorrent can now be considered as a good alternative to other bittorrent clients. It provides a lot of features such as:
- A polished Graphical User Interface written with Qt4 toolkit
- UPnP / NAT-PMP port forwarding support
- Encryption support (compatible with Azureus)
- Multiple simultaneous downloads / uploads
- Download from RSS streams
- An integrated search engine
- DHT (trackerless) support
- uTorrent Peer eXchange support (PeX)
- Directory scanning with automated download of torrents inside
- Good internationalization (~25 languages supported)
- Selective download of files in a torrent
- Media File previewing while downloading
- Torrent trackers edition and prioritizing
- Seeders / Leechers displayed in download list
- Styles support
- Files prioritizing in a torrent
- Torrent download in correct order
- System tray integration
- Tracker authentication support
- Unicode support
- Torrent downloading directly from their url
- Connection though a proxy
- IP Filtering similar to the one in eMule
Go ahead and try qBittorrent, you won't regret it!