There isn't any CPU that is "better for the future." 8 CORES sound tempting but it is useless, IMO, 5 years from now, most games would hopefully utilize even 6 cores. No game in the current and next gen(Frostbite 3, Distrupt, Unreal Engine 4) would utilize 8 cores or even 4. At a current point. You can see from here and decide yourself
http://www.anandtech.com/bench/Product/697?vs=701
Right now you are looking at a $200 CPU + ~$150 MOBO. Do you think it is worth it? For me, no. I would rather be investing it into say, a better monitor, speakers, peripherals, it may seems small but can provide a whole lot better experience. You would just be wasting ~$350 right now and right when you decide to upgrade. 3-4 Years from now, 8 cores/multithread, games won't use that much.
To answer your console question, console are made to last more than 8 years. You can't just take the CPU out and upgrade it or something similar, they are planned to made that in 2019, people would still go out and buy it even though technology in it are far behind, look at the PS3/XBOX 360.
Finally, unless you are doing some extreme work, gaming based won't utilize 4 cores for at least 3-4 years more.