Keep in mind, with the dual-boot system, when you re-install Windows, you'll have to re-install your bootloader, unless you want to try to use NTLDR as your bootloader. (I wouldn't recommend it.)
EDITED TO ADD: As for removing stuff from Windows... My best advice is just get a larger HD. You can try to limit the amount of stuff installed, but really all you'll end up doing is shooting yourself in the foot and causing yourself more grief as things randomly bomb from stuff being missing/altered. Personally, I'd rather waste some diskspace instead of giving Windows yet another reason to fall flat on it's face.