I have only one client who has moved to Windows 7 so this purchase would be primarily for research and development of their application. All of the others are staunchly staying with XP 32-bit, but I don't plan to carry 2 laptops around so will definitely have applications that need to run in XP Mode on this machine. Will I need to have install twice--SQL2005 in the 32-bit 'partition' (if that is how it works) and SQL2012 in the 64-bit?

Actually new features with Enterprise manager, SMS or whatever it's called this week are what kept me from upgrading for so long. It usually takes hours to figure out where Microsoft has moved a frequently-used feature that used to be at your fingertips. Even when you find it, it doesn't work like it used to, and Microsoft's documentation is seldom helpful. I'm less into toys and more into getting billable work done :-)