The 120mm fans seem pretty decent, but the 140mm I was expecting to push more cfm and be more quiet. For comparison the R4 120mm from Coolermaster pushes 70 cfm @ 19 db so that's pretty decent.
Edited by mark_thaddeus - 6/4/11 at 7:18pm
Here's a quote from an xbit labs test I read on the best 140mm fans:
"Scythe Slip Stream 140, Thermalright TY-140 and Thermalright X-Silent 140. These fans not only create the largest airflow at the same level of noise as the other fans, but they are also cheaper than their competitors. Moreover, Slip Stream 140 and TY-140 can be installed into the slots designed for 120 mm fans, which makes them a universal solution. Although we would recommend the manufacturers to include some vibration-absorbing mounts with these fans and make the TY-140 power cable longer. Note, that X-Silent 140 doesn’t have any of these drawbacks."
Here's the link for reference:
You might also want to check out the Air Penetrator series from Silverstone, they're very effective. They're quiet and they blow air directly in one direction making it a more efficient fan system.
Check this out: