Do you use water or passive cooling?
The hard drives on my beasts at home are the least of the problem comparing to the fans. Even with bigger slower fans with better blade design... Still louder than the HDs.
I used water during my intel q9400 days..
After i7, I stuck with air because the water pump churning-noise didn't justify the 100-200mhz extra ontop of air-cooled overclocking...
now my computer only has a single 120mm fan for the cpu onto of the other stuff that carry their own fan..
no other spinning going on in my room.