I have been using MRTG for a while but I always wanted graphs for more than network statistics. So I finally setup Cacti this week. It took me several nights of configuring but I finally got it setup like I want for my home network. The key for me was installing these cacti templates from Alexandre Dumont. I modified them slightly, and I may document the whole process on a friend's wiki later.
Check out the finished product here, this is Cacti on my home network