AMD 64 bit - Vista or XP

I have been looking to upgrade my machine situation. I have been using AMD Athlon 2.6Mhz, 2GRam, ATI 256MG for a few years. I have cleaned and tuned this throughout. Yet, it does slow down on some of my video editing work I do for mpeg and dvd. So. I have been looking at AMD 64 bit options.

Options:

a) AMD X2 with Vista 64 bit coming in a Compaq Presario (mostly because of the ease of having both a warranty and that I do not need to build it myself)

b) AMD X2 with XP 64 bit coming in a Barebones deal

c) AMD X2 with XP Pro coming in a Barebones deal

Obviously, I am asking if 3d Studio runs on a Vista 64 or XP 64; or, if it runs better on 32 bit OS, good old XP Pro.

The port I/O functions are 32 bit. So if you're controlling parallel ports with Gamestudio, use a 32 bit OS, XP or Vista. Otherwise, 64 bit should be fine.

Thank You. I am still looking. I cannot think of a reason for a parallel port use for a game. I will make sure that I do not need one before I do my final round of perusing my pc quest: to build or to get the whole enchilada.