Story: I enjoy watching the scrolling graph to see my download and upload speed, but often I would like to see a little more history that has already scrolled off the screen.
Request: I would like to request a graph or log file output of the up/down rate values that are displayed to me visually (every second by default)... something like MRTG graphs.
Use case: session log: I'm transferring files to/from an FTP server, walk away for coffee, and when I come back I'd like to see what the highs and lows of the transfer were. I could right click on the tool bar icon/graph and select "start logging" then come back and select "stop logging" and it could then prompt/display: a) scaled image graph of the logged session or b) an easily parseable text file with start time, end time, interval, and up/down measurements for each interval.
Use case: hour/day/week/month reports: like the session log case, but scaled to the last hour/day/week/month etc like MRTG graphs.
I hope you consider this feature request, and I think it could help answer many other requests as well!
 http://oss.oetiker.ch/mrtg/ - sample graph attached