Ok I'll give you a run down of the future rig:
Core i7 920 @ 4ghz + (with HT)
Gigabyte GA-EX58 UD5
6x1GB OCZ DDR3 1333mhz 7-7-7-21
Any brand HD5850 Plan to add another in 6 months.
Corsair Obsidian 800D
Sammy Spinpoint F3 500GB
2 x 12V laing DDC1+ Ultra 18w watercooling pumps
6 x 120mm Fans
2 x 140mm Fans
NorthQ 850W black magic PSU
I'd really like to keep the modular cables, I like a clean looking build and if theres no good reason not to get the NorthQ, then I'll go for it.
Never heard of the brand and can't find a competent technical review.
The general rule of thumb is a high quality 500 to 550 watt power supply with sufficient current (amps) on the +12 volt rail(s) can easily power an overclocked system with any single video card made. A high quality 700 to 750 watt power supply with sufficient current (amps) on the +12 volt rail(s) can power a system with two video cards operating in dual mode. There are a few exceptions like the new ATI Radeon HD 5XXX series cards which use less power due to their energy efficiency.
A high quality 500 to 550 watt psu will have a +12 volt rail rated at 40 amps. A high quality 700 to 750 watt psu will have a +12 volt rail rated at 60 amps.
In addition the power supply should be at least 80+ Bronze certified for energy efficiency. There are some models available which have achieved 80+ Silver and 80+ Gold Certifications.
Corsair, PC Power & Cooling, and Seasonic are some of the brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Some of the newer models come with a 7 year warranty. Lately we've been seeing a few other brands offering some high quality units. An example would be the Antec Earthwatts series which is a major improvement over Antec’s older psu’s like the Basiq models.