With the Windows 7 RC out today, and it being good for a year before expiring makes for a compelling argument to deploy it in limited production usage internally. I tested the Windows 7 Beta and was very happy with its stability and compatibility.
We do software development in virtual machines (using VMWare), so the OS isn't as critical (currently using everything from Linux to Windows Server 2008 on our developer desktops).
I have a new hire starting Monday and a 64-Bit Dual Core machine with 4 GB of RAM (More RAM on its way). I am considering installing Windows 7 on it as a test. Is it stable enough to run in a production environment? Any major concerns to watch out for?