We could run above sort of system with a decent 250W power supply :P, but there are no quality PSUs available in that range.
E5200 - 40W, GA-G31M-S2L - 35W, Transcend 2x2GB - 5W, 8600GT - 40W, Seagate 500GB - 18W, Optical Drive - 12W , total approx 150w @ load. Power consumption from mains...