This depends very much on your task at hand. However, since you're talking about making graphs from SVG, as usual XML.com is the place to look. Here is an article by Kip on creating SVG graphs, and here, here and here are Kip's three excellent articles on helping you choose an XML module for whatever task you have at hand.

Always check his column first - it's the most up to date resource on XML modules, and is even better than O'Reilly's book "Perl and XML" (IMHO).