I've got a system with similar specs and I use a corsair 750TX with no issues.
If you can afford it, I'd go a bit higher, that way down the road if you ever want to SLI you already have they juice, but if you aren't going to the 750 should work fine.
Just a note, my PSU isn't fully modular and I kind of regret not getting a fully modular PSU.
Happy building!