Not bad... I hope you don't mind, but I like to suggest upgrade paths for systems posted here.
First thing you should look into is getting an SSD. Doesn't have to be huge, but it'll be a significant system performance boost. They are as low as $130 for a quality 480GB SSD from Newegg. (http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&IsNodeId=1&N=100011693%204814%20600136715%20600076740%20600038499%20600038502%20600038492%20600038491)
If you want to go really high-end there are 960GB drives with good performance for as low as $250.
Second would be the PSU, simply because most better GPS will require more power, and that would be the biggest bottleneck for gaming in your system. Don't go for under 600w for a new one though, or 800w if you're thinking of doing multi-GPU. Also, higher rating is ALWAYS better, as it reduces strain on the PSU, and reduces power fluctuations that are sent to the motherboard and peripherals. (the fluctuations can get bad enough over time that it can literally fry the hardware in your system, usually starting with the RAM, and northbridge/southbridge of the motherboard)
I personally recommend the Rosewill brand. They are inexpensive, but good quality. A 600w from them with 80+ Gold rating is only $75. If you don't care about efficiency, you can drop down to 80+ Bronze rating for a $50 Raidmax PSU @735w. (Raidmax is another good brand with generally low prices, but not quite as good in quality as Rosewill in my experience)
Third is, of course, the GPU. Since you aren't likely to go spend $300-$500 any time soon on the previous upgrades, I recommend waiting for the Nvidia Pascal GPUs that will be coming out later this year. I don't recommend any AMD cards currently out (or in the planning stages) as an upgrade over what you already have, mainly because they aren't better on the price/performance ratio than competing Nvidia GPUs. Also, AMD can't make a professional driver to save their lives. (they have been known in the past to flat out ignore entire portions of standard OpenGL and DirectX code calls when deploying drivers, and I have personally been burned by them MANY times by AMD on various levels of GPUs, but never on the numerous Nvidia GPUs I've used and abused, even if they were cheap or old)
After those three upgrades, you'd really need to get a new motherboard/CPU/RAM setup for increased performance, so I won't get any further into the upgrades unless you'd like a full new system design made for you.
Right now I don't plan on upgrading anything. Maybe a used 4690k and a sdd. Also for gpus I wouldn't go with Nvidia since they lack Asynchronous compute for dx12.
