5 fans for a quiet system??
Its pretty easy really. A few low RPM fans. Better yet, variable speed fans.
Power supply:
Antec TruePower. Very quiet with variable speed thermal controlled fans (adjusts automatically).
CPU cooler:
I run a P4 2.4 @ 3.06 GHz. The stock P4 cooler is not quiet enough for me. I use an Alpha 8942 HS with a Panaflo L1A 80mm fan. 1900 RPM, 24 CFM, 27 dB. It cools very well and is much quieter than the stock HS/F. Beware of so called "quiet" 4000 - 5000 RPM fans!
Video card:
Dont know what you are looking for, but there are pretty decent cards with passive HS available.
Mobo:
Stay away from models with a northbridge fan. There are some now that have fan rpm controlling software "Q-fan", "Silent Tech", "CoreCell". This is a nice thing. I use SpeedFan to do pretty much the same thing.
Case cooling. Maybe add 1 Panaflo L1A 80mm. If possible, run from a mobo header and use Speedfan or a mobo with that feature to regulate the RPM based on system temp.