even with a heavy overclock your system will never draw over 400W from the wall, and most reputable PSUs nowadays will be able to supply enough current to run your computer so there's really no need to worry about that anymore.
a quality 500-600W PSU will be more than enough, cheapest I'd go is Corsair CX500, these have mostly solid parts, the only iffy part is the capacitors, which can cause problems if under a lot of load, but in normal use and gaming it won't have any problems, the only people who wouldn't use it are hard core enthusiasts who push their system limits on a daily basis.
As for what I'd recommend, it would be a Seasonic 520W, Seasonic is a thing of beauty in the PSU world, they are second to none and everything in their PSUs is a slice of power supply heaven, this product line (the SII12's) is Seasonic's bottom/value line and they are still considered some of the best on the market. Costs a bit more though, you can usually find one like 60 ish bucks I believe
and if you're really into high quality parts, Seasonic 550W gold efficiency, it costs a lot (about 80-90 bucks if IIRC) but I'm just listing it here for the sake of comparison