I'd strongly recommend the Corsair HX850:
NCIX.com - Buy Corsair Professional HX850W 850W ATX 12V 70A 24PIN ATX Modular Power Supply Active PFC 140MM Fan - CMPSU-850HX In Canada.
The price is a bit on the high side, but it's a Seasonic manufactured power supply with excellent performance. It does run a bit loud for my liking as I have an HX650, but other than that, it's an extremely solid unit. Plus, modular is always nice :)
As for kilowatt units, as suggested before, Antec makes very high quality power supplies. I believe there was a video on Youtube of the 1.2 kw model of the Antec HCP's delivering over 1600w's of power.