Dave Massy, from the Internet Explorer team, shares some of his favourite DHTML resources. Many readers (including this one) have, and continue to chime-in.
A reader has also educated me on the fact that the Gecko browsers also do support client-side XSLT processing. Dave Hyatt had made mention of XSLT in his blog a while ago, and appears to be making good progress. Here's to XSLT in Safari :) He's looking for test cases and it would appear people have hooked-him up quite nicely in comments. Dave, if you're still looking for more test cases, gmail me at frenchy.
Oh the possibilities of cross-platform, cross-browser, rich, accessible, web application development. Can you see me drool? <:D~~~