As it stands now, the big let down is that neither card maker could deliver a card yet that will handle true DX10 games. Even if you go top end now, or the start of 2008, your going to spend a good $500+ and know you'll be looking at >20FPS at high settings in a few big titles a year down the road. Most card buyers want to hold a $500 purchase for at least a year, more like 2 years in my case.
Both NVIDIA and ATI are continuing the ruse of putting large amounts of RAM on 6600/6800 era performance, giving these lame cards a flashy name like the 8400GT and putting them in boxes so flashy, they blind you when walking down the vid card isle at Best Buy. This shows a total lack of respect to customers and a total lack of integrity. This is worse then what Nvidia is doing now which is sitting on the 8800 series at top selling price till ATI poses any challenge, while keeping tight lipped about immediate releases. Most corps would do the same, but not as many go out of their way to blatently deceive customers.
Fact is, the 7950 GT OCed performs in the same class as a 8800GTS. Not as fast if the 8800 is OCed, but still close enough that gamers would notice little difference.
Nothing upcoming in the near term is all that exciting right now. If the manufacturers would only try for good performance with very low power reqs at the low end and extreme performance at the higher ends, things would be better for everyone. Card makers would have much better crossfire/sli sales at the low to mid end where most of their sales come from. Right now they'll have hoards of angry customers when Crysis arrives. People who figured their 8400GT with 512 DDR2 and a big 'Turbo Charged' certificate on the box, was actually a decent gaming card.
Pretty soon, maybe 2009, card makers will need to release low to mid low range cards that can handle current games, many of them with more and more DX10 features (with lots of presure on game devs by M$). If they don't, they could lose a lot of people to the console market.
Probably would recommend that people who need to upgrade now, hold for the 8800GT at a $200 price point. Probably mid-December. ATI at this point has too many problems- high heat, slow driver implementation, big hit using AA and still a poorer IQ compared to the 8XXX series.