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.
Yes, it seems to me that ASICs will not be a threat to the Ethash algorithm for a long time, because Bitmain did not manage to make ASICs which would be very different from GPU farm, and they will be producing them for a long time until there will be enough of them to severely increase hash rate on ETH, for me it is more scareful the reward reduction to 0.6 Etherium, and also ASICs under Equihash, because they will throw out many cards from Zcash on ETH.