PCI-E is faster than AGP in terms of data bandwidth, and of course is the new standard. However you can still get some excellent AGP cards, such as the X1950pro or the x1900XT. It's not so much the memory of the card, it's the GPU which determines how fast/good it is. There isn't that much proof to show that a 512mb card is any faster than a 256mb - but it can hold a little more detail/texture without having to load it from harddrive - useful for games with huge levels. A high end AGP card be it 256 or 512 would still beat a low end PCI-E card hands down. They never really pushed the 8x speed of AGP to it's limits, let alone the 16x of PCI-E. However, as PCI-E is the new standard, these cards will just get better and better. And of course with DirectX 10 now on it's way, these cards will just get bigger and better....the new 8800 series from nvidia are by all accounts, monsters!