As for example: Google Analytics charts, how would you do that? What other web apps do you know that have beautiful charts?
 Some commentary:
I've used Fusion Charts in the past (on tweetstats.com) and it provides some good looking and easy to implement charts. That said, it's Flash but it was the best looking option around when I implemented it back in late '07. Since then, there's been a nice rise in JS charts. gRaphael is amazing, but somewhat buggy and lacking documentation. Highcharts seems very complete and well-documented. I only came across Protovis recently, but it seems pretty darn awesome.
http://www.amcharts.com/ has an extremely comprehensive stock chart in addition to decent flash charts
http://www.rgraph.net/ is an html5 charting library you might want to look at.
I've worked with Fusion Charts for a while now, and their charts 1) have a very comprehensive API 2) are plain beautiful, especially the 3D charts.
JS charts look very promising, and I'm really excited about Highcharts and gRaphael.
If you're looking for something similar to the map component that Google Analytics uses, take a look at http://www.ammap.com/ or http://www.fusioncharts.com/maps/
@dacort - Thanks for pointing me to protovis. Expected it to be more of a hobby project (from the url), but was blown away by how comprehensive it is!
That said, how have you found the performance to be? Some of their demos are kind of slow, e.g. http://vis.stanford.edu/protovis/ex/candlestick.html.
Also, check out RGraph for HTML5 canvas graphs http://www.rgraph.net
Open flash chart ,an open source project:
I may be proven wrong and have to move to SVG/VML, but only time will tell. For now our focus is to build the best tool to put any kind of data in and get pretty graphs out.
Also, Theresa Neil posted a good list of 28 data vis tools here http://www.insideria.com/2009/12/28-rich-data-visualization-...