With the SharePoint 2010 released, we are all bounded to work on 64bit OS's, and my choice is still to virtualize since I can abuse the system as much as I want and revert back to original in seconds.
So, the problem is that the best performance we've got is when running win2k8r2 64 bit host and using hyperv to run win2k8r2 64 bit VM on it.
Works like a charm on my PC, but what happens when I want to have that VM accessible on my laptop? I do like my win7 there, and don't want to install win2k8 since it is a multi touch tablet which many things are not supported with a server OS.
Well, the options are to either use the boot from VHD option, which in my case was a pain since I had the VM created in and for hyperv.
The Other option I found was to install VirtualBox(.org) which let me run 64 bit VMs on my windows 7.
It also runs VHDs, most if not all - just straight out of the box.
I hit a problem with the latest one that when I booted a VHD created in hyperv into my VirtualBox it would boot into a blue screen every time.
The solution was amazingly simple though, glad I thought of it and didn't give up: See, when creating a new VM in VirtualBox, the VHD is added through a SATA controller. All I did was to remove it and add the same VHD using an IDE controller and boom! It worked!
(this was after a lot of trial and error of course... :)
Well, if you run into a blue screen in VirtualBox - Be sure to try and change the HDD controller!