One of the nice new features of the new Safari 3 beta is that it can display Scalable Vector Graphics (SVG). Check out an example image here.
[robg adds: As best I can tell, support for SVG isn't mentioned on Apple's Safari pages, nor in the Welcome.rtf file in the installer files. I won't be running any other posts on the features of Safari 3, so if you can provide detail on other new stuff you may have found (beyond the obvious new menu items and the features Apple has described), please add in the comments.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20070612150045672