I think Raphaël is a nice idea: it’s great for people who want their stuff to be compatible with old versions of internet explorer, and it makes it very easy to build trivial things.

To be honest though, I found that in trying to build anything more complex or with much user interaction, just working directly with SVG APIs and building up my own abstractions as necessary was easier and much more flexible. People shouldn’t be afraid to learn SVG: it’s pretty easy!

For anything driven by data, I recommend looking at D3, which is designed around some very powerful ideas.