a system running a single GTX 760 is recommended to have a 500W PSU, but that does not take any overclocking into account. Since you plan to overclock, I'd suggest adding 50-100 watts to the recommendation. The XFX 550 would be a good choice for moderate overclocking, but a 600W would be better for intense oc'ing. Get a quality unit from either Seasonic, XFX, Corsair (except their CX series if possible) or Antec. And if you plan on oc'ing your CPU you will need an aftermarket CPU cooler. For light to moderate oc'ing, the CM Hyper 212 EVO is a good choice, just make sure it will fit your case (I believe its ~ 160 mm tall).
Got the PSU. Works fine. The 24 Pin is really hard to get in. I don't think it ever really latched, but it aint moving. My Antec pops right into place so I know its not the mobo. Modular would be nice, but there's no NEED. Thanks for the help folks!