I7 7700k cooler

If you have 160mm available in your case, I recommend the lesser known scythe kotetsu with a 120mm fan for $35.
I have used one, and it is easy to install, effective and quiet. Much better than the popular hyper212.
Here is a review:
http://www.silentpcreview.com/article1391-page1.html
It is good enough for a modest OC.
As of 6/9/17
What percent can get an overclock at a somewhat sane 1.4v Vcore.

I7-7700K
4.9 83%
5.0 62%
5.1 29%
5.2 6%

If you are going for a maximum overclock, look at the noctua NH-D15s with a 140mm fan for about $85.

If you have less room, say 145mm, the cryorig H7 with a 120mm fan.is about as good as you can do on air.

Less than 145mm , you will need a liquid cooler which I am not fond of as a rule.
My canned rant on liquid cooling:
------------------------start of rant-------------------
You buy a liquid cooler to be able to extract an extra multiplier or two out of your OC.
How much do you really need?
I do not much like all in one liquid coolers when a good air cooler like a Noctua or phanteks can do the job just as well.
A liquid cooler will be expensive, noisy, less reliable, and will not cool any better
in a well ventilated case.
Liquid cooling is really air cooling, it just puts the heat exchange in a different place.
The orientation of the radiator will cause a problem.
If you orient it to take in cool air from the outside, you will cool the cpu better, but the hot air then circulates inside the case heating up the graphics card and motherboard.
If you orient it to exhaust(which I think is better) , then your cpu cooling will be less effective because it uses pre heated case air.
Past that, A AIO radiator complicates creating a positive pressure filtered cooling setup which can keep your parts clean.
And... I have read too many tales of woe when a liquid cooler leaks.
Google for AIO leaks to see what can happen.
While unlikely, leaks do happen.

I would support an AIO cooler primarily in a space restricted case.
If one puts looks over function, that is a personal thing; not for me though.
-----------------------end of rant--------------------------

Your pc will be quieter, more reliable, and will be cooled equally well with a decent air cooler.