Apparently PCI Express 2.0 graphics cards will work in PCI Express 1.0 slots--though they won't have the added bandwidth to play with.
So, I'm thinking of getting a better graphics card... but I'm a bit astonished by the kind of power supply the high end stuff wants (not even getting to the question of SLI!). I thus have to ask myself: what do I think is good enough? After all, I made a point of getting a CPU with low power consumption. I don't want to run my electricity bill up for a few extra fps. (Have you seen those kilowatt and above power supplies? OMG!)
I hope that graphics card companies are looking towards efficiency rather than just throwing more hardware at the problem--not just so I can run SL nicely on a netbook, but so I can get good performance without using my graphics cards to heat the house.