My system has 2 more SATAs, another dvd, floppy, sound card, and a few case fans with a x1900xtx, and pulls 235 watts at load according to the meter on my Thermaltake purepower psu. (FEAR)
So yes, you should be more than adequate for the rig you described.
I laugh at the 750+ psu's some folks think they need. Most high end rigs, sli/crossfire included, pull less than 550w from the wall. Having a kill-a-watt to measure actual vs wild guess helps too!
Quality almost ALWAYS matters more than quantity.
I ran my dell 3.2 p4 with dual sata, dual dvd, 1.5 ram, floppy, misc add -ons, and the x1900xtx on the stock 380 psu with nary a blip for 6 mos. I did upgrade, as I was worried about the 12v rails.