Make sure you dont strip too much out of vLite, you will find things stop working, like the installer for instance.
Try and avoid anything that you would class as essential for the system, the guide link I put up above is pretty good and the posts afterwards give some useful pointers.
On my mini after installing Office 2007, firefox, acrobat reader, itunes, blackberry software, Kaspersky, starcraft (original and broodwar and the installer exe's) and VLC my windows directory stands at 6.22Gb. Program directory is at 3.13Gb.
(Apologies, I didnt check the size of Windows straight after install but the post which I followed as well showed 4.33Gb of space used for the Windows installation.)
Along with the aformentioned software and a bunch of docs and films my 32gb drive shows 16Gb used and 12Gb free.