Re: Do we really need those beefy powersupply's?
Yes you do need a beefy power supply. I have the Corsair AH850 in my desk rig.
I have been building computers for many years and I have found that if you don't plan for worse case scenario with what you installed and then plan ahead, you'll be shelling out for a bigger power supply later on.
Video cards are not the only major current draw in a computer. You have to figure the CPU, RAM, HDD(s), video card(s), sound card, optical drive(s), wireless card, mother board, fans, and of course, whatever bling bling you've added in.
You have to figure with all devices running full bore that there's some watts being sucked down. If you speculate on what you need with out doing the math, you're going to come up short and be in the market for a bigger power supply.
Why buy twice when you can plan ahead and only buy once?