Wang,
Forgive me, but I think you heard a buzzword and jumped from an unfounded assumption to a foregone conclusion.
PCI Express is, from what I can find out, only on Intel mobos, and while there are non-video PCI express slots (which are, to me, surprisingly small) the only PCI Express
cards I have seen are video cards which fit into a dedicated PCI Express video slot.
I don't think that you are going to see the demise of the PCI slot anytime in the near future. I just learned of
another hot video technology by Nvidia that goes by the letters 'SLI'.
Here is the (apparently) first incarnation of
that technology.