Noone mentioned MLDonkey. Am I the only one using it?
It's very great, as it's running as a background daemon on my dedicated server, so regardless of what I do to my computer at home, my Torrent client is always online.
I guess mldonkey takes some getting used to, and it's especially not easy to configure if you really wanna seed some torrents, but if you're just concerned with downloading, it works out of the box (on ubuntu at least^^)
It comes with a telnet- and a webinterface. So where ever I might be right now, I can check on my torrents.
(yes I know, most BT clients have a webinterface...)