VMware workstation allows a maximum of 950GB. That's quite a bit more than VirtualPC 2007 allows. So what's my advise on sizing? As before, do the max.

Windows Server 2003R2 install makes 1,637,548,032 byte .vmdk. Still under 8% difference.

"But I don't want to pay the extra 117MB." Really? That's pretty cheap compared to what the space required to install a partition resizer later along with your time.

"But I'm only going to use this virt for a couple of things." Great. Then when you are done and delete it, you'll get a full refund of your extra space.

"I don't want my virt blowing up my main machine by causing it to run out of disk space." You could enable disk quotas.

Don't be a cheapskate when VirtualPC 2007 asks you how much disk space to allocate for your machine. Do the max! I just did a comparison of three identical installs of Windows Server 2003 on a 8GB, 64GB and a 132GB (which is the max) disks. The difference? Less than 2.5%. Here's the numbers:

8GB - 1,514,532,352 bytes
64GB - 1,537,721,344 bytes (22MB more)
132GB - 1,552,535,040 bytes (36MB more)

But why pay that extra space? If you ever had to grow one, you'd know why.

But why 132GB? I don't even had that much space on my drive? Sure, but the beauty of a virtual disk is that you can copy it off to another machine.

That's a key point: Your virtual machine may outlive your real hardware.

I'm gonna guess the difference on VMware is similiar.