Mine's very quiet.
Antec P183 case, all Scythe SlipStream 120mm fans. All fans mounted on anti-vibration rubber mounts, same for HD/Optical drives. SSD for main OS. Aftermarket (Scythe Mugen something or other) heatsink+fan for CPU, GPU fan is from Arctic, not sure the exact model off the top of my head.
CPU: Intel Core i7 4770k
GPU: ATI Radeon R9 290x
RAM: 32GB, Corsair. Too lazy to look up the timings.
MB: Asus Maximus 7 Hero.
I live across the street from a gas station, and the sound of their HVAC system is louder through closed windows than my PC 1m away at idle. Under heavy load it becomes audible, but I use headphones which serve to mitigate that quite well.