OK, I agree the Noctua heat sink double fan cooler, is the very, very, best there is (if you have £60-£65) to spend... Its only justified in my view if you want to beak the 4Ghz wall... and it goes on easier than other coolers and its rock solid.
Personally I've been persuaded to go Titan Cooler £35 for my next project .... As its just 1c degree higher in most i7 860 P55-UD6 benchmarks, sometimes its its even matched the Noctua heat sink.'
So for nearly £30 less, I can live with 1c. "So bare that one in mind bro..."
The "Terbinator" is the very best Guy to ask about aftermarket coolers.