Your comparing a single current gen GPU against 2 last gen GPU's...its gonna be the same result on each generation, you speak of 8800GTX v 7800GTX, what do you think the performance figures would be like with 2 7800GTX in SLI against 1 8800GTX...hmm similar me thinks. So when you wait for your DX11 card do you think there will be that much difference between 2 GTX285's against 1 DX11 card...methinks no.
I think your trying to delude yourself into thinking waiting is best....enthusiasts dont do that, they buy the best there is now. Granted not many people can afford to do that in this day in age of recession but if you want what is best now then you have to pay for it...and 3 GTX285's in tri sli wipe the floor with 2 8800GTX's in sli.
Heres a couple of benchies with 7900GTX v single 8800GTX..sorry i couldnt find any with 7800 but 7800 and 7900 aint that much difference.
Half life 2 lost coast
FEAR extraction point
.E.A.R. Extraction Not - FSAA 4x - Anisotropic Filtering 16x
You see my point ? 2 last gen cards will always keep up or near enough keep up with a single current gen card....
So if it is money you are wanting to save arent you better keeping hold of your 8800 sli setup and upgrading to GTX285 SLI when the DX11 cards are out ??? I do agree that there is no need to pay huge amounts of money to upgrade to current gen if your not gaining that much but there is no sense in your methods...surely its gonna be cheaper to get GTX285 in sli than it is to buy a next gen DX11 card single and have near enough the same performance...there seems to be a lot of contradiction in your posts.