Sorry guys, disagree.
6Gb C drive is sufficient. Install all your programs on say D drive and then create another partition (E drive) for data.
Then use TweakUI to move a number of "special folders" on to your data drive.
I have moved My Docs, Favourites, and all my e-mail to the data drive. Tweak will also let you move things like your desktop etc. You then have it all in one place in an easy to back up location that can be FAT formatted and easliy recovered under dos. Win2k/XP etc can then run in NTFS, rather than Fat32 and if windows goes pop, you can format and re-install without losing your data!
Of course, you all have a robust backup system in place, don't you? So this isn't necessary is it?