Er, no, you don't need 650W-750W. 500W-600W should get you going well as long as you get something from like Seasonic or Corsair. I threw the build in http://extreme.outervision.com/PSUEngine
and it suggests about 367W for just the CPU, motherboard, HDD, an ODD, the other parts add a handful of watts. And I can never seem to get their numbers when I run a game and measure off the wall (it's lower than 60%, which is the lowest they'll go)... so in reality, the system should take up 250W playing a game.
Case in point, I'm running my rig on a 450W 80PLUS Gold Seasonic PSU and it's packing a i5-4670K (OC'd to 4.0GHz) and a GTX 670. The worst I've seen it go is 230W off the wall.