Fellow MVP, Rolly Perreaux, pointed out on his blog:
How many of you went to your Microsoft TechNet Subscriber account to get the latest and greatest Office Professional Plus 2010 OR Project 2010 OR Visio 2010 today? I’m sure quite a lot, if not all of you did.
Now many of you immediately went and downloaded the 64 bit version? After all, your computer’s operating system is probably Windows 7 64 bit right?
You cannot install the x64 version if you have any 32-bit Office applications, such as Sharepoint Designer, Microsoft Frontpage or previous versions of Visio. The x64 version is also incompatible with most or all Office Add-ins (primarily a concern with Outlook).
Either way, know that you have to uninstall any beta versions of Office 2010 before you can install RTM.