Depends on your bottom line really but I never suggest budget PSU's, as in a way that is the most important part of the system.
First the wattage.
The 280x is going to pull 350W at full load. Pretty dang high.
The 1600x is going to pull about 175W at full load slightly more with an OC, should be under 200W.
The entire rest of the system is going to pull between 100-200W depending on how many drives you have. Keep in mind these are the high end values but you still want a buffer just in case they DO require full power.
Given your CPU and GPU, i'd say a 750W minimum for you.
Personally I don't like to recommend EVGA because I hate their products, but they make a darn good PSU. The lowest quality I can recommend is a EVGA Supernova G3.
If you want to go the high quality route, there's no PSU I have come across that matches the Seasonic Prime Titanium in performance. You can also go for the Gold version and save some money, but that one should fall somewhere between the EVGA G3 and the Seasonic Prime Titanium as far as performance goes.
I like the Prime Titanium because it is dead silent, comes with a 10 year warranty, and is sleek as hell and not to mention comes with absolutely fantastic cables (and more than you will ever need) and just has a really great premium product feel to it.
But yeah I guess if I had to.. i'd even put the EVGA in my system.
Below that in quality it get's a little risky.