If I enable HTML minify now that I am running WordPress 3, I get this error on the bottom of every page.
Fatal error: Cannot redeclare class JSMin in /home/war59312/public_html/wp-content/plugins/w3-total-cache/lib/Minify/JSMin.php on line 53
Though looks like the page is still being minified just fine, so looks like a bug introduced in WP3?
Update: Development Version @ http://wordpress.org/extend/plugins/w3-total-cache/download/ fixes this bug when using WP3. :D