What is a reccomended amount of power supply i should use in this System?

Hellbus91098

Honorable
Feb 3, 2014
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10,520
CoolerMaster Hyper 212X CPU Cooler
G.Skill Turbulence II RAM Cooler
Microsoft Windows 7 Home Premium 64bit with SP1 OEM
CoolerMaster Silent Pro Gold 800W
Samsung 840 EVO Series 250GB SSD
EVGA GeForce GTX 780 Superclocked ACX 3GB
Seagate Barracuda 2TB ST2000DM001
Intel Core i5 4670K
Corsair Vengeance CMZ16GX3M2A1600C10 16GB (2x8GB) DDR3
MSI Z87-G45 Gaming Motherboard
CoolerMaster HAF XM Case with Window
 
There is another aspect as well. That is system noise. On some power supplies, you can set the PSU fan to come on only when the PSU hits a certain percent usage level. So if you select a slightly higher PSU wattage (high efficiency PSU's) then under normal day to day activities the power supply is essentially fan-less.