Zero77 :
Is more recommended to use an aftermarket, but if you are not going to do overclock or like me GAMING for 10 hours (COD or BF) at 1080p and online.
Then yes, you will need a after market cooler
Most games don't put all that much stress on the CPU. Especially with a multiple-core CPU the load is usually fairly evenly spread and you probably wont see much more than 60% usage across the cores. Most of the demand during gaming will be placed on the GPU. Almost all newer GPU's have more than enough cooling to keep themselves cool, and so is of no concern. Case cooling will help, but an after-market CPU cooler will give no real advantage here.
Best thing to do in your position:
Build your system
Keep the stock cooler
Download "HWMonitor" (open this program on start up and it will measure your highest, lowest, and current temps)
Before you shutdown your PC after whatever you've been doing, check your highest recorded temps
If the highest CPU temps are something like 70 degree's+ consider buying an after-market cooler
Anything below 70 (60-65 is usually about the highest load temps you'll see) is perfectly fine
Don't spend money on something you might not need, it just isn't worth it and the money could be better spend elsewhere on the build.