Yesterday, Microsoft published Knowledge Base article 970789, which provides details of a problem that affects the 32-bit (x86) English-language version of Windows 7 build 7100. The problem, in short, is that the installer incorrectly sets access control lists (ACLs) on the root of the system drive.
I agree the temptation to get the Win 7 RTM is high.. but to me it's just not worth it.. I mean think about it this way, the overall purpose of the RTM is to "smooth out the rough edges of the RC" meaning as far as differences/changes go they will be almost non-existent.. Mainly because Windows 7 is already so stable/solid and contains very few bugs compared to Vista..
Now when Vista was in RC stages and going to RTM yes, it was well worth it to download the RTM because of the large amount of bugs that were in the Vista RC.. (unfortunately the RTM didn't solve all of those bugs as we all know ). It would have actually seemed like a "better/changed" version of the OS in Vista's case.. I just don't feel that is the case with Win 7..
That's how I look at it anyway.. I'm not saying if you have the chance to download the Win 7 RTM don't, I'm just saying I won't be and that's my reasoning..
Yes the RC will work for a year.. March 2010 is when it expires and that's when the bi-hourly reboots will start.. However, the Final version of Windows 7 will in fact be released this holiday season (as confirmed by Microsoft) so you'll be able to purchase a final copy of Windows 7 long before the RC expires..