I'm the one who mentioned not to use Gruff. Rmagick leaks, Gruff had
plenty of bugs and the whole thing is a pain in the neck to get working.
We're now using Google Charts (forgot which Rails plugin) and live has
been much easier. I'm sure there's plenty of other good solutions out
there. If you can live with Flash or Javascript, quite a few charting
libraries exist for those (and they're quite nice as well)
Carl Mercier, founder & ceo
Karabunga Inc.
...makers of Defensio.com