Graphics card Rankings
It's not pointless I guess but at the price point there is better options. For a hundred bucks less you can get either the 4870 1GB version or the core 216 which are great cards. The core 216 is newer tech than the 280. While the 285 and 295 are the newest Nvidia cards.
i guess to put it another way you need to look at money to performance ratio.
you can get more of a feel for the graphics cards by reading about benchmarks and testing. In most games the 280 is about 3-5fps better than either the 4870 1GB/260 core 216. 100-125 dollars more isn't worth an extra 3-5 fps.
The 285 has about a 10-20 fps just on the 48701GB and the core 216. but it is also 430 dollars!! that is like 200 dollars for a 10-20 fps increase. Which isn't very good either.
The fps between a 4870 1GB and 4870x2 is 30-50. which is a much larger jump. but the 4870x2 prices have dropped to about 450 bucks. (200 dollar differance or less)
the fps between a nvidia 260 core 216 and there new 295 chip is about 40-50 too. but there new card is around 500 dollars. (250 dollar differnace or more)
these benchmarks are coming from high resolutions and just take them very loose, not exsact here, just giving you a feel.
Also you can find benchmarks for the certain games you want to play, sometimes ati cards play games better than nvidia and vis versa.
example: Nvidia's SLI scales much better in Crysis, while ATI cards play the game GRID a lot better.