Skuzzy has said several times that there is no sense speculating like Z06 has said.
Even AH in its current form can crush the fastest systems out there if you crank the reflections/environmental tab to max. If I max out every detail setting, put on the max anti aliasing and AS settings, then fly in busy areas with lots of tanks and planes in view, I can see 30fps and a lot of notchiness with a 4930k 780ti system. Paradoxically, you can run a pretty modest system with full detail and reflections off or on just 1 notch, and see great 60fps fairly consistent performance. So, who really knows what the future will bring. Hopefully the beta will give everyone a good idea of what to expect hardware requirement wise.
As the previous poster said, staying flexible and being patient are your best options right now IMO. If you need a system now, focusing your resources on your graphics card is probably the best thing you can do. Any decent CPU from 2500k up to 4790k will push a good GPU pretty well, for the mid 300$s you can get one of the faster cards for the $ out there, nVidia's 970 card. Building a decent 1150 socket system with that card can be done in the 1000$ range, check out Kool's thread here - IMO with something along those lines you'll probably be just fine with whatever game you play, including the new version of AH when it comes out.
