I've had experiences where a document looked very different in OO.o than in MS Office. It's not something I want to take a chance with. I also used to use my XP partition to play some games, and I may again in the future. A few GB isn't a big deal.

There's no way I'm paying for vmware or for crossover office, and I'm not pirating them. I got XP and Office free from my college. I'd rather not give any money at all to anything dealing with MS.