I’ve been experimenting with an addon to MRTG called “gbgraph.
GBGraph creates informative graphs showing total data transfer for the month, daily data transfer, average daily transfer and more. Because my ISP iiNet only meters incoming data, I modified GBGraph to only graph incoming data and ignore outgoing data.
Currently I’ve got gbgraph running on eth1/iinet (external interface), eth0 (internal interface) and jupiter-lan (my laptop ethernet).