I would recommend Corsair PSU. Have the Corsair VX 450W and it's still running perfectly at the moment, though the fan sometime will be slightly noisy.
Also recently bought the Corsair TX 750 V2 for my new Ivy Bridge build.
Used to have Cooler Master Silent Pro M700. It's extremely quiet and running perfectly as well though I do not have OC.
The reason this is, is because the PSU was tested at 750watts, meaning it can do more but not guaranteed. GOOD PSUs can handle what they are speced at and then some. A cheap 850watt PSU will most likely fail at 850w or close to it. If you go beyond spec your 80+ silver will no longer apply, it is only applicable under 750w.