http://www.techradar.com/news/best-pc-power-supply

A power supply is one of the most crucial computer components, but perhaps least scrutinized when putting together a computer. So much of your build can be made or broken by a power supply, which is why it's so important. After all, a $2000 custom build has absolutely no use without juice.

A poor quality power supply can also cause enormous headaches down the road. When the power supply starts to fail, it isn't always obvious what the problem is. One day, you're playing a game and suddenly your computer crashes and reboots. Troubleshooting is only fun when you get to the root of the problem quickly, so buying the right part that's free from potential troubles is a solid investment in your computer and your personal sanity.