If you go by silencepcreview.com
The top quiet fans are late loons, nexus, noctua, and the scythe flex series.
They all are in the "best" category for best sound and decent CFM's.
Now for my personal choices and suggestion.
If i was going to get some I would get the Loons, becuase they are the cheapest by far, but still comparable to the rest.
BUT, i would not suggest those, if your looking for the best cooling and performance then i suggest 2 things.
1. A fan controller. For anyone looking for sound and performance. I own the Vantec/nexus 205 $16 at newegg. It controls all the fans in my case.
I personally choose the scythe F series. Its has the most CFMS out of the Group (70cfms at 12v) compared to the rest that fall somewhere around 40. Ther difference is its somewhat noiser at 12V. But at 7V, its whisper quiet, and you get about 40 CFMS.
So you get the best of both worlds in my opinion. During regular use, you get great CFMS and WHisper quiet, and when you need some extra fan action you can turn them up, and get 70 CFMS and still ok sound. Its the quietest 70 CFM fan i have ever owned.
you sound like you want quiet and fast air moving, so to me, your a prime candidate for a fan controller.
Just my 2 cents.
Heres the review
silent pc 120 mm review