http://humdi.net/vnstat/ It's in the repos and also has GUI vnstati. GUI demo page. http://humdi.net/vnstat/cgidemo/ Hah, this is cool. Only installed yesterday, works perfectly. You can monitor multiple interfaces as well. Just check man vnstati. Can be transparent as well like this .png I just saved. (eth0) Graph on the right shows 24 hr. day activity.