Good choice on going with the 7700k. Years back I did comparisons between non-HT and HT running in games and some general applications (some that utilized it and didn't utililze the HT).
Really overall over the years of having HT or not I always prefer to have it at least there in the back ground. Its easy to disable it if it becomes a true issue but overall these days its have very minimal to no impact in normal computing anymore thanks to advances. Years ago we'd have issues that if a program could use 2 or 4 cores... it could use that HT "core" first before using a true core. This came with a performance hit. These days it only benefits to have HT overall, especially if you have a low core count system (Dual Core with HT for instance).
Even in my testing with a laptop and working with software that is mostly single core driven, having the HT threads are beneficial for "multi tasking". Unless you really want to conserve power, it really isn't that big of a hit Wattage wise either, couple watts at least on a laptop. For desktop reasons, keeping it on is the best way to utilize the full potential of the system. Especially if you do mutli tasking or photo/media/renderings.