I've just started using Monowall. So far I am very impressed with it
especially the traffic shaping features which I find invaluable.
One feature which I would find very useful is real-time bandwidth
monitoring. I personally find this feature useful to diagnose problems
on the network. I see traffic graphs on the to-do list. Personally I
mainly find traffic graphs useful if the graphs are updated every few
seconds. Effectively giving real time feedback.
An example of what I mean can be found here
http://www.mythica.org/bandwidth/. Admittedly it is crude, but I found
it did the job well with my previous router. The programs called bwbar
homepage is http://www.mythica.org/bwbar/.