http://www.pcgamer.com/best-gaming-pc/

The best gaming PC isn't one you buy: it's one you build. Building PCs can be a very expensive hobby, but that doesn’t mean you can’t get a great, powerful build for a reasonable price. Not everyone needs to play games at 4K, after all. The trick is to build a PC that will offer impressive performance now while still delivering the power needed to play games at least two to three years in the future.