There are tons of good non flash ones. Someone mentioned Protovis, which is neat, but last I check it wasn't supported in IE. There is also Flot (jquery) and

There are tons of good non flash ones. Someone mentioned Protovis, which is neat, but last I check it wasn't supported in IE. There is also Flot (jquery) and Flotr (prototype), and a handful of others. I use a modified version of Flotr, and it works great.