Hi Gauntalus,
Nooo, don't do that. WinDoze pretty much needs to at least think it's on the first partition. It's also simpler to install WinDoze first as it's going to clobber the mbr on your drive.
Yeah, you can use grub to make Windoze think it's on the first partition. But is it worth the effort? Not in my book, just let it have it.
Yeah, you can install Windoze after Linux. You better have a boot disk, or repair CD handy to reinstall your boot loader. Or you can use ntldr to boot Linux, it works well. I did that for a couple of years. Simplest is install Linux second and just use grub unless you have a usb keyboard, then you want to use lilo.
hda1 XP Pro ntfs 10 gig should be plenty
hda2 /boot ext2 32-50 meg (it's past cyl 1024, but that an anchient limitation)
hda3 swap 1.5 gig is OK, but it'll probably rarely use it, 1 gig should be plenty unless you're going to be doing something pretty heavy duty.
extended partitions for the rest of the drive
hda4 / ext3 or reiser 10 gig s/b plenty
hda5 /home 1 or 2 gig s/b plenty
hda6 /vfat the rest of the drive
Always keep home on it's own partition, if you hose your install you can just reinstall and you keep your files in /home and that saves all your personal settings. You'll like that little feature...
Just leave the firat partition and you can install XP later, but you will have to reinstall grub. gentoo.org has an excellent grub install guide in the install docs.
good luck, have fun
