The first thing to clarify is whether you NEED i7 & 16GB RAM, over i5 & 8GB of RAM. For gaming, it gains you nothing. For stuff like high-end photo/video editing or 3D CAD, it's worthwhile; not for much else. Then do you have an interest in overclocking, itself, or just for the performance gain, it gives you. If the later, use something like Asus P8Z77-V Pro, or possibly ASRock Z77 Extreme4, for mobo and mid-tower case. If the former, then go with something, like the Maximus, but recommend you get full-tower with it. If you only want modest overclocking, something like CoolerMaster Hyper 212Evo, is ideal low cost cooler. If you want to get a bit more "drastic" with OC, then a liquid cooler, like Corsair H100 is worth considering.
OnePlus 5 review