What's the point in searching for a quiet GFX card and then filling the tower with 6 MASSIVE fans ? I have a stock cooler on my Core i7 920, nothing in front of the HX750W, one 12 cm PWM fan at the rear and one 9cm PWM fan for two HDDs and the temps are nicely low and I bet it's quieter than yours. I personally never liked the idea of spending money on those grotesque heatsinks and numerous fans.
Don't bet...you'll lose your money. The 120mm fans are running at 550rpm, the heatsink fans are running at a constant 900rpm. The case has aluminium/plastic/aluminium side panels + noise absorption foam, the only noticeable sound when playing at night is the videocard fan speeding up, but not by a great deal. The point of spending money on big heatsinks and fans is to get the most amount of airflow with the least amount of noise.