It turns out that I had to be running new 64-bit versions of isapi rewrite, PHP and coldfusion in order to get my IIS functional in 64 bit mode. Coldfusion 8.0.1 now has full Vista SP1 support - http://www.adobe.com/support/coldfusion/downloads_updates.html. However, I had to uninstall coldfusion and then reinstall it first. Don't forget to back up the xml files in the coldfusion8/lib folder so you don't have to recreate your settings/datasources/mappings. PHP x64 binary can acquired here: http://fusionxlan.com/PHPx64.php - I had to manually add the fastcgi module in order for it to work. People said you could just turn CGI on and off, but it didn't populate the fastcgi option. www.isapirewrite.com is what i use for URL rewriting.
I hope this helps someone. I certainly lost a lot of time figuring it out!