Good call using NVIDIA over AMD for your GPU.
Definitely get an Intel CPU. Something like a 4690/4690k would be more than enough for any gaming you're planning on doing. If you wanted to save money, you could even buy an older generation processor such as a 3570K/2500K or something, since the technology really hasn't advanced that much since then and if it could save you some substantial money it would be worth doing, in my opinion. The only downside is that you'd need to find a compatible motherboard with the correct CPU socket.
If the money you'd be saving by doing that is negligible, however, then scrap the idea because there's no reason not to get the best if you're only gonna be saving 20 bucks or something by rolling your CPU back a generation or so.
As far as the cheap/upgrade later vs "instant gaming rig" option, all I would say is don't cheap out on your motherboard, PSU or cooling. A decent i5 would be a good enough CPU for any game atm, and as far as a GPU goes a GTX 970 will run pretty much anything you could want, or a GTX 960 would also be a good option if you're not ready to spend that much yet. As for RAM, get 8GB and then upgrade to 16GB if you feel like you need it later (it's not really necessary for any game atm). However, you don't want your components to fail because you have a bad quality PSU, and you don't want your expensive hardware to underperform because it's always overheating!
And then a decent motherboard would allow you to upgrade pretty much your entire system to literally whatever you want in the future, although there may be some CPU limitations depending on the motherboard socket you've picked.
When I built my first PC, the PSU died within 3 days because I bought some cheap no-name crap and figured it'd be alright xD Learn from my mistakes because I certainly felt silly when it happened