I'm probably worrying way too much about this, but here goes: If I get a new G5 with three PCI-X slots, and a couple of years down the road PCI-Express becomes the standard, is my choice of video cards going to become more limited than they already are as a Mac user? Is there any chance that new video cards would be backward-compatible with PCI but NOT PCI-X? I keep reading about how PCI-X is going the way of the dodo. Even if PCI becomes obsolete, it will at least be an extremely common obsolete technology, so I could probably expect some legacy support. If there is any risk, is there any offsetting benefit for using PCI-X for a casual user? Thanks in advance for any advice you can provide!