I can reduce Win2k/XP's memory usage to between 35 and 90 MB, depending on things like driver size variations.
There are install guides on my site you might want to have a quick run-through (
www.legolas.com/wac/), aside from getting the usual crap from running on startup.
When picking new hardware for PCs I tend to check how big the driver downloads are... souncards with 20MB drivers for example aren't my first choice :-)
