Yes I agree with everyone on board, simply because technology is advancing so fast that there is simply no point, it is like waiting for the next iphone.
However, from a PC gaming perspective, I have did some research and heavily considered getting the 780 ti now, simply cuz its the best of the best in terms of Keplar GPU's and the new Maxwell, however efficient they may be, 230W compared to the Keplar's 350 ish give or take (dont quote me to heavily on the numbers) do not have benchmarks to ultimately conclude if the performance increase is really worth it. Speculating the pricing to be around the same $700 ish, it would be better to go for the 780ti's. ALSO not to mention when the 800s do come out there will be a massive price drop on the 780 ti's which means u would be able to buy 1 or 2 more to do SLI with. At this point go with 780ti and until u hear more and see more later there isnt a compelling reason to wait. Another HUGE HUGE reason is the wait for the nonreference gtx 800s. Say you wait for the 800 reference, u will then want to a couple months for the non-referenced editions from other manufacturers, and that in my opinion would be a huge pain in and of itself.
Hope this helps =)
Austinomical :
I am making a new gaming build from scratch, as mine is totally outdated. I have been researching for months, and I thought I had my build ready to go (link below to my part list if interested). But I recently discovered that the next gen gpus are coming out soon for Nvidia, the new Maxwell architecture. Should I wait, or just build my pc now?
http://pcpartpicker.com/user/Austinomical/saved/4lnh
case: Corsair graphite 760t