George Lazu said:
The pascal architecture is announced for 2016, and yes, will require special motherboards to run it. That said, a newly released GPU and a newly released motherboard [which will probably be high-end] will not come cheap. If you do have a lot of money for such a PC, hold onto them until both the GTX 1080 and the appropriate motherboards [none have been announced yet] are released. Otherwise, you should make your build however it suits you, and in 3 or 4 years, when the pascal architecture becomes cheaper and more widely spread, then you might make a new build
Can you please link to where Nvidia explicitly states we'll need new mobos for Pascal?
Otherwise you're guessing.