Um, there's one major problem with this video: people are going to expect a 450-550W PSU to power a high-end gaming system with a 2600K and two GTX 580s. lol Even a high-end 650W wouldn't be enough. It might for some games, but you'd never be able to overclock and you wouldn't be able to relax, that's for sure.
With two GTX 580s under full load in their system, their PSU pulled 719W from the wall outlet. That's about 200W more than what Linus got because he wasn't running a realistic gaming application! Now, Guru3D's CPU was idling as well, so a 2600K at stock adds 95W of power and overclocked to 5 GHz would add about 150W. So, 150 + 719 = 869W. That's 869W being pulled from the wall outlet. That means if the PSU is 90% efficient while pulling 869W from the wall outlet, then the computer is pulling 782W from the PSU. So guess what: a good quality-made 750W PSU might be enough, but I would recommend a good quality-made 850W PSU just to be safe.