It depends on the game you want to play. Games are starting to push past 8GB for recomended and in some cases min settings, so its a matter of if you want to invest in RAM now or later.
As for your build, there are some problems.
Cooler: It's not really a problem so much as an unneeded expense that could be put towards other parts. You don't need the H7, you're not OCing and your CPU comes with a cooler. You can pop one on if you want the lower noise factor but it's not going to do a whole lot beyond that unless you live in a hot climate. Cheaper for quieter cooling than stock would be a Cryorig M9i.
Thermal Compound: If you're getting an aftermarket cooler like the Cryorigs, you can stick with that paste or go for something a bit better if you want to throw down cash on it.
RAM: You're over spending. Your motherboard can only support up to 2400, *edit [strike]so 3000 is wasting cash.[/strike] normally DDR4-3000 would be a waste. RAM prices are wacky right now so it's oddly about the same price.
PSU: It's kinda a lowish grade PSU
HDD: The blacks are nice, but for the price I believe you can get in to a larger HGST HDD with the same warranty.
SSD: I'd highly recommend one for a new build if you can budget for it.
OS: You didn't list one. Kabbylake isn't supported by Microsoft with Win7 so you're gonna want to go with Win10 for a new build.