This is your best bet. Trust me, restarting is not that bad. The more RAM you have, the shorter the XP startup takes. It will never be shorter than OS X thoIf you can afford to buy Parallels but you can't afford XP as well, maybe you should just buy XP. You can find XP very cheap online. Sure, you would have to reboot into Windows each time you wanted to play a game but Boot Camp is still the fastest way to get Windows apps on your Mac.
If you ever manage to get a copy of XP, one of the games demoed running under Fusion was GTA3.....Sorry I was ignorant to the fact that you need a full copy of windows for Parallels, silly me. Lucky though in a way that I don't have a copy of windows as it shows I've never had a windows pc in my house! Thanks psychofreak for the link, testing it now!