So, if you're okay with running a Qt based applications on your Gnome desktop and have nothing against the excellent KDE :D, then qBittorrent is one of the best Torrent clients that you can find!. It's a cross-platform utility and can be run on Windows, Linux and Mac OSX, etc as well.
*. Search easily - Rather than opening your web browser and entering the URL... qBittorrent lets you easily search within popular torrent tracker web-sites via its built in "search" area.
*. Update/remove tracker information.
*. UPnP / NAT-PMP port forwarding support.
*. Bandwidth scheduler.
*. Encrypt the protocol (helps to unblock torrent file downloads which are sometimes blocked by various ISPs)... are few to name.
If you run Ubuntu 10.10 then you can install qBittorrent using the below command...
sudo add-apt-repository ppa:hydr0g3n/ppa
sudo apt-get update
sudo apt-get install qbittorrent