Get an 80 plus platinum PSU that provide what you need (eg don't buy a 1000W PSU when you need 500W. You want your PSU to operate at around 80% of its max. do you want modular? do you need single or dual 12V rails? pick a CPU  Understand what you're getting, if you dont know the difference between an i7, an i5, and an i3, why are you picking one? understand what hyperthreading is and whether you need it or not (you probably dont need it and if