Based on my assumptions about fans and other devices, the PSU calculator at http://www.extreme.outervision.com/PSUEngine still showed <500W for your rig. Allowing for even more margin, something like a 550W XFX PSU would be good for that build.
550W XFX PSU is enough but assuming K series and oc gpu this need more power
Nope, it doesn't. With overclocking and capacitor aging thrown in, it just hits 501W, with 451W minimum. As good as the Seasonic-built XFX is, I'd be confident in it. Oh, the other two are also good PSUs, but over 600W is simply not needed.
That's good to hear. I have a 750w corsair in my budget, and I'll be overclocking. But will it be enough to power 15 case fans? I'm getting the Antec Lanboy air.
Oh, ouch...with 15 fans in there, the suggested jumps up to 600W, +/- depending on how many of them are LED fans.