Thats not completely true - Adobe has got some completely brilliant Graphics, Audio and Video Programs for Windows; industry standard programs. And I have personally seen many Mac Reports about Video Editting from people who do it and even make a living from doing it saying how dreadfully annoying it is. It works, its good, but its tempermental.
And - you're trying to base OS X, probably Jaguar maybe even Tiger on XP; which is 3 Years Older!
If you buy a PC now - you will be able to Upgrade to Longhorn quite easily when its out. I recommend the PC Option.
Unless you are used to Mac?