I would be i9, GTX 1080ti, good ram and motherboard. For gaming I prefer Nvidia anyway (despite the fact that AMD is on the same level) + intel's processors are great.
Btw building a GPU mining farm isn't that risky, making asic for ethereum or possibly for other coins in near future, still doesn't kills GPU mining because there are other and profitable coins too + there is a potential that some of them may rise.