I'm currently taking a look at all the libraries and will test the functionality over the next days. Some of them are realy overweighted - especially the D3-based libs seem to be slower than the others.
http://plot.ly does everything I've ever wanted and more with pretty good API. The fact that I can use the same API first for doing data exploration in python or R and then when publishing the results to the web is a nice added bonus.
After using several different libraries over the past few years, I've started using D3.js on its own. While it's more work than dropping something ready-made into an app, it's more flexible.
If you have specific designs/requirements to work from, it may be easier to build the charts with D3 than trying to shoehorn a stock chart into matching the spec. Behaviors like linking chart interactions to independent components (or vice versa) become easier to implement as well.
I'm currently taking a look at all the libraries and will test the functionality over the next days. Some of them are realy overweighted - especially the D3-based libs seem to be slower than the others.
I'll keep you informed about my "test winner".