I'm a huge fan of Raphael and the development momentum seems to be going strong (version 0.85 was released late last week). Another big plus is that its developer, Dmitry Baranovskiy, is currently working on a Raphael charting plugin, g.raphael, which looks like its shaping up to be pretty slick (there are a few samples of the output from the early versions on Flickr).
However, just to throw another possible contender into the SVG library mix, Google's SVG Web looks very promising indeed (even though I'm not a big fan of Flash, which it uses to render in non-SVG compliant browsers). Probably one to watch, especially with the upcoming SVG Open conference.
