Hey Folks,
I've been using the Windows 7 (64 bit) RC1 for a couple of weeks now, and I LOVE it! Well, except for the fact that 32-bit Shell Extensions will not work with 64-bit Explorer.exe. If you hunt around the net and the MC forums you will see some workaround to run the 32-bit version, however that doesn't work in Windows 7, it will not run the 32 bit explorer.
Anyway, I found out that if you run a 32 bit alternate Explorer/File Manager they all work, so for the times you need the Media Center shell extensions to work (which for me is mainly the "Import" context function) it works fine.
I am using the free FreeCommander at
http://www.freecommander.com/. But you should be able to use any other one.
I am hoping that the MC crew add a 64 bit Shell Extension soon - from what I am reading the whole app doesn't have to be made 64 bit, you can add a 64 bit shell extension to the 32 bit app. Also, get ready for 64 bit, I have heard that Windows 7 is the LAST Microsoft OS to offer 32 bit.