I have been looking for a nicer terminal bit torrent client than bit tornado for a while and came across rtorrent. It has its own wikipedia page. I have found this torrent client to be much faster than the official version.
It is easily installed on Debian and Ubuntu systems with
$sudo apt-get install rtorrent
NB: if $apt-cache search rtorrent does not return any results you may need to add some thing to your sources list.
On OS X it is available once you have installed and setup Darwin ports.
$sudo port install rtorrent
Good tutorial here for getting it running