I recently migrated to the 64bit edition of Microsoft Office 2010. My main reason for doing this was that I wanted to make use of the RAM in my machine with PowerPivot, but it certainly didn't come without a bit of pain. The most notable parts there were that I had to convert a bunch of 32bit API calls in my VBA to 64bit compliant calls while preserving 32bit compatibility for the other machines in my office. Despite my initial intimidation here however, some good friends helped me out and I was up and running within a few hours, and I know believe I understand how to migrate the rest of my code easily. (I may post on that in the near future.)
One challenge I did face though was that you cannot run Office x64 on the same machine as Office x86 (32 bit). To install Office x64 you must uninstall any 32bit version of Office programs first. This means Visio, Project, Office 2007, Office 2003, etcâ€¦
My challenge with this is that I teach courses and like (need) to have multiple versions of Office installed so that I can teach in the appropriate versions. I could use a full blown virtual machine, but the problem here is that I find it inconvenient when trying to teach. I can't flip back and forth between the app and my presentation easily, my presenter mouse doesn't work in the VMâ€¦ it just doesn't work.
So when I installed Office x64, I was a little disappointed. I really wanted to run it side by side with Office 2003 and 2007, but I couldn't.
But then, in a discussion with one of my staff yesterday, we ended up chatting about Windows XP mode in Windows 7. It IS a virtual machine, but it allows you to run an app installed in the VM as a program from the host (Windows 7) desktop. Here's a shot out of my start menu of the applications I installed in the Windows XP Mode VM:
So this is pretty cool. I've been able to have Excel 2010 x64 open and running on my laptop, and I was able to successfully launch Excel 2003, Excel 2007 and Excel 2010 (32 bit) all together.
The Windows XP mode apps all run on the virtual machine, so they are segregated from my host operating system which makes this possible. I also installed SmartIndenter and MZTools in the VM, and those both show up in the VBE for the apps when I launch it.
I'm really impressed with this. Granted it's far from perfect application level virtualization, but it allows me to do what I need. All the issues I mentioned above are solved with this. I can run all the versions of the app together, and they seem to run seamlessly.
If you are running Windows 7 and want to check this feature out, here's the link: http://www.microsoft.com/windows/virtual-pc/download.aspx