Ironically, right before I was ready to install the RTM of Office 2007 Professional, I saw a post titled, Office 2007 won't upgrade from a prerelease version of the 2007 Office System - Office 2007 Setup Spelunking from Scott Hanselman about some issues he had had with upgrading Office 2003 to 2007. 

He had some great information about how to uninstall some things from beta versions of office 2007 that do not necessarily appear in the standard Add / Remove programs feature in XP.  He used a tool called MyUnInst which I ended up having to download also because I ran into a similar problem.  But my problem even went further which was very frustrating.  Even after removing anything that had to do with Office 2007 beta, which I never installed on my system anyway's, but found some of the same files Scott did, I still could not install. 

So I thought well, I have this program called Expression Designer Beta 1, maybe that needs to be removed also.  So when I tried to remove it, it said I could not uninstall it because of some language thing.  What?  So I downloaded and reinstalled the Expression Designer Beta 1 and then uninstalled it fine.  Then Office 2007 installed.

Well all that frustration ended up being worth it.  I love the new outlook 2007.  That alone is worth the upgrade for me.  I really do like having feeds integrated in and the integration of ie7 and office for adding feeds could not be more seamless.

Now I doubt many consumers will have the problems I had, but for other early adopters beware of the betas you have installed and make sure to remove them all to get a nice install of Office 2007.  It is definitely worth it.