I'd take those specs with a pinch of salt to be honest. I've seen no conformation of those numbers by other sources. And if those specs are for real, it'll be a freaking monster (sizewise) and thus extremely expensive. 1800 million transistors is just ridiculous for a single chip, even at 55nm. The only Nvidia card I have seen some good evidence of is the 9800GX2, and that is mostly a 8800GT times two as far as I've seen (onboard SLI).
Furthermore AMD has the HD3870x2 (onboard crossfire) coming up before the 9800GX2 and with that they may actually be ahead in single card (but dual chip) performance for a little while. Then there's the R700 (or RV770) which will also appear some time in 08 so I think AMD is looking better now than they were when they released the HD2900XT.
It seems the graphics industry has hit the brick wall the CPU guys hit a few years back so you won't be seeing these extreme improvements over previous gen we've been used to. Looks like it's going to be tweaking of existing architectures with some multi-chip action from here on out.