Alright. I sat down and tried to do some research. The following is what I've found in order of quietest to loudest:
Manu | Model | RPM | CFM | dBA
Vantec | Stealth | 1500 | 53 | 28
Titan | TFD-12025L12B | 1800 | 71 | 29
Panaflow | FBA12G12L1A | 1700 | 69 | 30
Titan | TFD-12025M12B | 2000 | 79 | 30
Titan | TFD-12025H12B | 2200 | 85 | 32
Thermaltake | A1280 | 2000 | 78 | 34
Vantec | KD1212PMB3 | 2400 | 84 | 35
Sunon | KD1212PMB3-6A | 2400 84 | 35
Panaflow | FBA12G12M1A | 2100 | 87 | 36
Vantec | KD1212PMB2 | 2800 | 98 | 37
Dynaeon | DF1212BB | 2200 | 92 | 38
Panaflow | FBA12G12H1A | 2500 | 104 | 42
Sunon | KD1212PMB1 | 3100 | 108 | 42
YS Tech | FD1212387B-2R | 2800 | 131 | 45
Actually, I was a little surprised. The only 'low noise' fan that I've ever really heard of before was the Vantec Stealth. In my search I quickly found rave reviews on the Panaflow L1A. As you can see, it's <i>almost</i> as quiet as the Vantec Stealth, but moves a lot more air.
One thing that completely surprised me was stumbling across the offerings from Titan. For the same level of noise as the Panaflow L1A, a Titan TFD-12025M12B moves considerably more air! So far the Titan TFD-12025M12B is my 'quiet 120mm fan of choice'.
I was also amazed at how loud some of these 120mm fans are. I thought the general purpose of them was to move a lot of air for not a lot of noise. Yet there are some loud ones in the group. There were much louder fans than the ones that I listed. I tried to keep this list at the cusp of 'quiet'.
So anywho, this is my starting point. If anyone knows of any specialized fans, pricey or not, that could also fit into this group, please let me know. I'm not too impressed with what I was able to find, but it's better than nothing.
<font color=blue><pre>If you don't give me accurate and complete system specs
then I can't give you an accurate and complete answer.</pre><p></font color=blue>