go for the 6 cores, they perform excellent for its price, 1070 for example, I myself run 1055T and it runs anything i throw on it with 5850CF.
I run clustering for servers so I buy pretty much only amd for myself, cost is far too high to replace the whole cluster, all old systems becomes server cluster upgrades.
usually buy the cheapest things that deliver acceptable performance.
Those with the latest and greatest in hardware like to complain about how stagnant graphics are these days because of consoles, but it's great for the rest of the unwashed masses to catch up and enjoy decent graphics at affordable prices. I don't see the need to upgrade from my Athlon II X2 250 for another 2-3 years, hopefully a used Phenom II X6 can be had for $50 on ebay by that time
I just regret going too cheap when building my PC a year ago, my Radeon 4650 can barely run modern games at 720p at decent fps (trying to hold out for the Radeon 7000s series before upgrade GPU).