What are you all on about the 6800GT beating the X800 XL. Have you not been reading reviews of graphics cards in the last 6 months!!!?
Listen up Rhenerie, the X800 XL performs practically the same as the 6800GT; obviously in some tests the Nvidia wins, in others the X800 XL wins but overall they are equal in performance.
However, as you say, the ATi costs much less, which overall makes it the better card.
Every single website/magazine I've seen has been saying that the X800 XL is THE chip to buy.
Just to consolidate what I've said, I've just sold my 6800NU (PCI-E, 256MB), to buy an ASUS X800XL for £200.