i have 2x120mm case fans and a 92mm and no they don't make much noise. then theres the 120mm on the psu, 120mm on the cpu, gpu fan, chipset fan and an 80mm for airflow to ram.
Just one 120mm case fan at the rear of my PC. I had to replace the original Sunon MagLev because it kept making ticking noises. Ball bearings must of worn out, so I put an Antec SmartCool fan there instead.
System is quiet most of the time. Although my mobo CPU sensor measures idle temps around 50°C and load up to around 60°C. Don't think the mobo sensors are accurate. Only loud when fans spin up around load but not too distracting and doesn't too often.
Noise mainly comes from my annoying Seagate Barracuda 120GB 7200 drive when seeking. Annoyingly loud! Sounds like a hedge trimmer or someone dragging a wheeled suitcase across concrete!