New
#31
Once the RTMs are out you will want to backup everything in order to preserve your contacts and other things in order to see all that restored later on the final product. From what I hear you could restore backups from Office 2000, 2003 on the 2010 once out.
The product keys for the actual RTM releases wouldn't be expected to even work on any beta to start with. This is why there is a definite expiration date to begin with. It's the same as seen with 7 where you can't use the retail keys on either RC.