Video Cards?

Can anyone tell me what the best video card there is avaliable and how they actually work?

These two are the top of the line from Nvidia and ATI.
Both come in AGP and PCI express versions.
Expect to pay in the area of $600. to $700. US.

1) NVIDIA GeForceFX 6800 Ultra

2) ATI Radeon X800 XT Platinum Edition

Basically they work by converting digital information (zeros and ones) into analog information that can be used by the monitor to light up pixels and create a picture.

It is a very complex procedure using many components, drivers, etc. not easy to explain.