bill - 4:22 am on Nov 15, 2007 (gmt 0) With Vista you'd be wise to allocate more.
On my XP workstation I have 16GB just for Windows. I put my Program Files in another 20GB partition. Both of those are getting a bit full of late though. If I were to reformat this system I'd give windows 20GB all to itself and I'd allot 30GB for my apps.
With Vista you'd be wise to allocate more.