-x2 GTX 470 OC'd to 800/1700 (1.087v)
-i5-750 OC'd to 3.411ghz (V-core 1.27, cant remember they other voltages)
-x2 2Gb 1600mhz RAM (I think its 1.6v)
-DVD/CD burner drive
-x1 320Gb 7200rpm HDD
-x2 1TB 5400rpm Green HDD
-x4 120mm Fan (3 w/ LED's)
-x2 140mm Fan
I went to eXtreme PSU calculator and it said that I would be using 650w's but that does not sound right to me, so I jus wanted to ask around and make sure that I am not putting to much strain on my PSU.
A good 850 watt PSU can put out about 70 amps of 12 volt power. Two GTX470's will use a bit less than 30 amps. The other big consumer of power is the CPU. Figure about 10 amps. That will leave plenty of power for the rest of the system.
I think that a 650 watt PSU would be cutting it kind of close.