I just released a case study (click on the blog post title or click here) using the commercial software charting package called "AnyChart". After using over a dozen charting solutions including Google Charts and FreeCharts I really feel that AnyChart has the best solution that really scales up. Not only does AnyChart have a large number of charts but it is also very reasonably priced at around $500USD per server. Because I store all the chart specification and implementations in XML and I use eXist to manage the charts it is easy to manage the full lifecycle from requirements to testing all within a single Lucene-search powered environment.
The latest release of AnyChart also generates SVG and HTML5 compliant charts that run on the iPhone and iPad. This really shows how "declarative" systems are much more portable than any flash-based implementations.
If you are looking for an inexpensive but powerful tool for building charts and dashboards I would defiantly give them a try.
You can get samples at their web site at anychart.com