Raphaël is small JavaScript library that should simplify your work with vector graphics on the web. In case you want to create your own specific chart or image crop-n-rotate widget, you can simply achieve it with this library.
Every time Dmitry has demo'd this at work I've been blown away. Basically it allows you to do cross-browser graphics manipulation in Javascript by providing an abstraction layer on top of whichever is available out of SVG or VML. MIT licensed, "supports Firefox 3.0+, Safari 3.0+, Opera 9.5+ and Internet Explorer 6.0+â