Originally Posted by BStoltman
So what are the following components on a graphics card, since it seems they don't make that much of a difference based on what has been said about.
They're all important, but what matters most is the type of GPU. No GTX 260 is going to be significantly better than any other GTX 260. The ones that have higher core clocks are just overclocked, and you can do that on your own to a cheaper model for free. Same with the memory clock.
The stream processors are important, but whether you get a GTX260 with 192 or 216 SPs, its still going to be a really nice card. The SPs are basically like mini processors that calculate fancy graphics effects. They don't control everything (there are other factors that determine how quickly your game is rendered) so they aren't necessarily the most important spec to look at.
More is better, but with most high end cards like this they're all going to be very similar, so don't bother spending $50 more for a similar card with a few slightly higher specs.
It gets more complicated with low end cards though because two cards could have the same model (for example a 9500GT) while one might have half the SPs or half the memory clock speed of the other. Luckily, no one does this to high end cards so you're rarely going to see more than a couple percent difference in performance between cards.