The last PC I built cost around $600 for the parts - and it was pretty nice, IMHO. Back in the day, I kept up with the Nvidia vs ATI thing and actually purchased a few "expensive" (meaning over $100, in my skinflint world) graphics cards to scratch my gaming itch.
These days, though, the current crop of high end cards are so out far of my price range that they may as well be made of solid gold - and some almost weigh as much.
That said, Nvidia has pulled off quite a trick with their new GTX 1080 - it's apparently not far behind their Titan X card in performance, but uses a lot less juice and is about 60% of the price of the flagship card.
BGRThe consensus seems to be that the GTX 1080 is a fantastic card at the price point, and a big step up from previous generations. But unless you need that power, there’s no point upgrading from a 900-series graphics card. If you’re a new buyer, it’s no real competition. The 1080 (and its cheaper sibling, the 1070) are the cards of choice.