In no particular order: http://g.raphaeljs.com, http://vis.stanford.edu/protovis, http://highcharts.com, http://www.fusioncharts.com/ (Flash)

[edit] 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.

A few more:

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!

Plug: For dynamic US state intensity maps I created the tool http://www.flashusamap.com/statistics.php

we use protovis for our graphs and it is pretty damn awesome. The cross-browser support (no IE) is an issue until IE 9, but it's pretty incredible stuff. I'm no designer but they make it easy to make pretty complex charts.

The lack of IE support is what kills it for us. We need to do some charting stuff, and we'll probably end up extending gRaphael or Grafico or something and copying several of the Protovis charts.

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.

performance hasn't been an issue. The demos are some pretty intricate stuff and for the most part not made for performance. Even most of those have been speedy.

Flot (http://code.google.com/p/flot/) has treated me fairly well, but a coworker swears by highcharts.

Google Chart Tools lets you generate images for static charts, or create interactive charts using their javascript library: http://code.google.com/apis/charttools/index.html

Also, check out RGraph for HTML5 canvas graphs http://www.rgraph.net

They use Flash.

http://code.google.com/apis/visualization/documentation/gall...

Open flash chart ,an open source project: http://teethgrinder.co.uk/open-flash-chart/

I made Grafico: http://grafico.kilianvalkhof.com it's an opinionated SVG charting library with excellent documentation and lots of customizable options.

Very nice...btw, the example entitled "Line graph with multiple lines and a watermark" is just showing the grid and labels in Opera 10.54 on Windows.

Thanks, I'll look into it! Opera is a fickle beast ;)

I'm on the ZingChart team - we render charts in both HTML5 and Flash. So far we've gotten great feedback. Our charts are JSON driven and can plot huge data quickly [demo] http://www.zingchart.com/labs/blog_charts/10k_points.html.

http://www.zingchart.com http://www.twitter.com/zingchart

I use HighCharts(http://www.highcharts.com/) at press9. Javascript, very nice charts.

Plug: Give my startup Pretty Graph a try (http://prettygraph.com). We are trying to build the best web-based graphing tool. Still in very early stages, and looking for early users. I was going to make a review post here soon, but since you asked now I thought I should mention it anyway.

Are your charts all images, or can you generate SVG/VML charts?

By default, our charts are images for cross-browser compatibility and speed, but we can produce SVG too (not VML at the moment).

I'd recommend SVG+VML...making an image chart startup may be a little like going into the horse-and-buggy industry just as the Model T is coming out.

Ha! I'm aware of that. However, I think the format of the graph output is not the most important/unsolved/annoying problem in making graphs from my users' perspective. The key difference here between our product and the other libraries and apps mentioned in this thread is that we are primarily building an end-user application, not just a library for developers to use (although our API will also allow that).

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.

I used http://pchart.sourceforge.net on http://wappalyzer.com. It doesn't look like the developer actively working on it anymore though.

You can make static-PNG charts with http://matplotlib.sourceforge.net or http://volnitsky.com/project/mplw

if you're on a .Net platform, you may want to take a look at Dundas Data Visualization http://www.dundas.com. Just try to avoid the defaults :) We use these for data vis at http://allegiance.com.

Also, Theresa Neil posted a good list of 28 data vis tools here http://www.insideria.com/2009/12/28-rich-data-visualization-...

http://visifire.com, I've been using this cool set of open-source charts. Look no further if you are searching for beautiful charts.

http://www.jqplot.com/ is one that I've been using lately.

Thank you all.