3 Options:
1. AMD system - will want to overclock (spend extra on PSU/cooling/motherboard), will still deal with low FPS in some DX11 games, count on things getting better in games that use DX12 (which will not be all new games). No real upgrade path. Leaves more budget than i5 for video card.
2. i3 - Better FPS in *most* DX11 games, shows limitations in a handful of current games (e.g. 64 player BF4). Will improve with DX12. Has an upgrade path. May save money over AMD system due to smaller PSU/cooler requirements, leaves most budget for current video card.
3. i5 - Future-proof CPU, will not likely need upgrading but has option of i7. Less money available for video card, but banks on the idea that a CPU's useful life is much longer than a video card's - spend the most on the component with the longest useful life, and least on the most quickly obsoleted component, at the expensive of some performance today.
i5 can be either Haswell or Skylake. DDR4 will likely get cheaper and DDR3 more expensive, which is in favor of Skylake, but a Haswell system will save a little bit of money today.