Today GPU are amazing ATI using HD 3870 X2 while Nvidia Using 9800 GX2 but I choose Nvidia couse is the fastest GPU on Earth

The nVidia 9800GX2 might be a tad better, it's a LOT more expensive.

About Crossfire X and Quad SLI, ATI also has my winning vote, because Quad SLI doesn't work very well just yet and it's really expensive since you can only apply Quad SLI on the highest-end cards.
Crossfire X is actually quite a good invention, because you can combine multiple GPU's to work together without them having to be the same. nVidia has introduced a similar technology, of which I forgot the name right now.
Those are interesting technologies, it really makes me curious what wonderful things you can do with it in the future.

Id go with CrossfireX because the other week i saw the 3870x2 sell for $300 on ebay~! was tempted to buy it. Id wait until the 4k series cards come out because its rumored that there will be a card thats 2x as fast as the 3870x2; possibly on a single PCB again.

Nvidia 9 series is Not bad


But I think crossfire is better...