More than enough... I haven't been on tom's lately but I can be certain it would run the rig with no issues, considering its FX 8350 and R9 270.
You may visit pcpartpicker and enter your rig there to get near accurate power usage estimations.
do you ever plan on upgrading anything, especially the video card? if you do and you go with a much higher tier card you will want a higher wattage power supply. how much are you spending on that cooler master gx 550w?
A quality 750 watt should do fine. I have a firstname.lastname@example.org, OC'ed 280X, h100i, 3 drives, a few leds, fan controller, and I've never seen more than a 400 watt draw according to the kill-a-watt meter. That's with a 850 Seasonice gold.
@Mad - Yeah because its not needed.. the PSU is capable of providing high wattage but the system does not draw that much power at its maximum.. A 550W PSU should be able to drive your rig easily as well.