FYI, we run an app that used to use Highcharts too, but we discovered flot and never looked back: http://code.google.com/p/flot/ Wanted to share in case that's useful to you, too! (In particular, it will come in handy if you ever need to develop a web app for commercial purposes, as Highcharts has a tricky licensing scheme for web apps.)
Thanks, I appreciate it. Descriptions are on my TODO list, but have been on the back burner in favor of more projects. I will have to bump up their priority.