Yeah, with that budget the i7 4790k would be a great choice. It sells for ~$280 at micro center, a good z97 board is $120.
As for the gpu's, I'd stick with two good 970's. Either EVGA superclocked or Gigabyte Sniper G1. The G1 is faster than the reference 980 gtx, but only costs half as much. Of course the 980 could be overclocked and beat the 970 again, but for even for 4k gaming I'd doubt the benefit/price point.
And for 1440p, even a single 970 would suffice for great framerates.
As for ram, 16 gb are really enough. I'm with 16gb and never even come to use 8gb, except for rendering really large files.
As geofelt said, 1866mhz cl8/9 is enough. I'd personally just pick the cheapest 1866-2400 mhz ram you can find, they are often very similary priced until that.
And if you can, put in a noctua nh-d15. Greatest performance/noise ratio there is. With outstanding performance, too. On the same performance level as a h100i, sometimes even a bit better. While the h100i is at 46dba and the noctua keeps quiet at 34dba.