you can slap a 128mb PCI video card in there, since they are 32-bit, very few video cards were produced for the 64-bit PCI Bus compared to the 32-bit
you are all seeming to get it confused, there is the standard PCI Bus which is 32-bit, then the PCI-X bus (seem on server motherboards) which is 64-bit.
if a video card is 64-bit, 128-bit, or 256-bit, its the memory interface within the card itself, so basically desiboi, you can use any PCI video card you will find on that site.