I don't run bittorrent at all (nobody on the home network does), mainly has to do with my current employment. Between my room mate and I we do 200 GB on average, we've had one warning sent out for getting to 245 GB.

Here is our yearly usage chart: http://i.imgur.com/wZbU1.jpg (since the router/gateway was last rebooted). Do note that there is NO illegal downloading at all. NetFlix, Hulu, Pandora, Spotify, Steam, Dropbox, WoW and many others.