Use temperature-monitoring apps such as SpeedFan to ensure you have enough cooling after finishing the build.
SpeedFan is a hardware monitoring software that is able to change fan speeds according to system temperatures.
In the SpeedFan application, you should look at the Core # for the best temp gauges.
You may need to play around with the number of cooling fans, fan speeds and temperature levels over time to find out what nets you the best balance between good temperatures and good noise levels.
Congratulations! You have completed building your own HTPC.
Next, I would recommend checking out my software guides to learn more.