I've got say I agree about no need to add ATI cards, as they are easily comparable with the selection of nVidia cards shown in article.
But it lacks comparision with single core CPU's. In the times of 6800GT's popularity we've had single core Athlons like Barton, and perhaps early Athlons/Semprons with 754 socket. As adding AGP system would complicate things way too much, I think at least Athlon64 socket 939 could be used, as those were very popular in between/during 6800GT and 7xxx series.
At very least we should have one set of benchmarks on low/old CPU like that, so we can see if buying faster card is of any use at all, or will we reach a bottom of performance the same way that we see 6800GT unable to use additional power from new CPUs.
Other than this, it's a great article!
PLEASE - make one more roundup like this once GT200/4800 cards are out!
P.S. And nice to see that 9800GTX, and overclocked Q6600 are still right on 300W consumption, meaning any quality 400/450W supply is more than enough for them!