Personally, if just for gaming, I'd hang fire and wait and see what the 4c/8t and 6c/12t R5 ryzens have to offer. They're closer in spec to the 7700k (the 1300 and 1400, 4c/8t, versions are the closest, with the 1500 and 1600 versions having 6c/12t). I reckon these "might, should, hopefully" overclock higher than the 1700/1800 skus due to having less cores, taking them closer to the performance of the 7700K and the 1300/1400 spec cpus will be cheaper than the 7700K also. If it overclocks well, I think the 1500/1600 range is the most promising due to the extra 2 core and 4 threads.
Pure speculation on my part I know but I reckon its worth waiting and see how these lower skus do when released. You never know, they might get up to 4.5ghz or maybe 4.7ghz with reasonable temps and, if they do, they could match or beat the 7700k at 4.8ghz-5.0ghz, you never know.