At school, we have a plain Windows Domain Controller, no RM system or similar, imaged with FOG. I've just been setting up Windows 7 images and have noticed that, by default, if you simply give the Windows 7 install wizard a whole harddrive to use it seems to partition it up in to two partitions, with one being a small utility partition of some sort. However, I've had FOG image everything as "single partition" systems and they seem to boot fine after imaging. What is that small partition - swap space?
For servers (for instance, on my home system) I tend to assign each virtual machine separate volumes for OS, data and swap. My home servers only have a single RAID array each, plus an OS boot disk, with the RAID volume split into logical volumes via LVM rather than via partitioning, but ideally I suppose I'd have the OS for each machine on a smaller, fast harddrive, data on a RAID array (maybe a separate array for each VM) and swap on an SSD, with the OS for the physical server hosting the VM booting off USB and loaded entirely into RAM.
The 100 MB system partition is used primarily as BitLocker partition for BitLocker encryption. Additionally, it also holds the Windows Recovery Environment (WinRE) and boot files with boot manager for booting up the computer for troubleshooting when there is no Windows 7 installation DVD disc on hand. (Source)