Video editing benefits from a moderate GPU. It doesn't have to be the very best. I would get the 5820K (3.3 base, 3.6 turbo). It's base frequency is almost the same as the 4770K (3.4 base, 3.9 turbo) and the turbo probably doesn't work on all cores simultaneously. You can also overclock the 5820K probably past 3.9 GHz. Video editing benefits from a combination of fast cores and multiple cores.
Since your gaming is moderate, the 5020K and GTX 980 should be fine.
If you don't want to overclock and don't already have a MB, the i7 6700K would be neck and neck with the i7 5820 and a bit better for gaming. Personally I think that an overclocked 5820K would surpass an overclocked 6700K, but have no testing to back it up.