Huntor is a full-featured command line Bittorrent client. It currently has no GUI. This client focuses on being run in the background, such as on servers. It is highly customizable. Its disk storage layout makes it easy to incrementally rsync the data to a different machine while downloading.
ioAmuleAdunanza is a port of the well-known eMule P2P client to the Italian Fastweb MAN Networks for Infodomestic Objects (Linux/BSD) with an intuitive interface. It is built with SpatialBundle technology, so it does not require installation nor any administrator privilege access.