PCI-Express slots

I'm about to buy a computer for me, and saw that motherboards are now offering PCI-express and common PCI slots, and graphics cards will probably no longer be using AGPx8.
My current Geforce MX, which I was bringing with me, only works on AGP.
I'm thinking about buying a PCI only motherboard though, which will support in the future PCI-e x16 cards as well as DDR2 ram since it seems to me that buying an AGP motherboard and that only supports up to 400 DDR ram or so won´t last long.

I read a lot to understand what I wrotte so far, but I'm still confused :)

Take this for example: Radeon X300

Since it runs on PCI-e x1 and not x16, would it have the same performance as an AGPx8 128MB graphics card?

AGP isnt going to be forced out or outdone for a while yet.

Uhm, I think it´s better to stick with AGP for now. I'll change the motherboard in the future if it needs, instead of buying a new equal graphics card now.
Even though they will be arround the same price, I'll end up with a better motherboard in the end.

Thanks RoD