The Best Air cooling I found was:
Noctua NH-U14S for Intel LGA 2011,1156,1155,1150 and AMD AM2/AM2+/AM3/3+,FM1/2 Sockets, U Type, 6 Heatpipe,140mm
+ Noctua Ultra Silent 140mm Fan NF-P14 FLX (Brown) (Second CPU Cooler Fan)
It keeps my CPU temp between 30ºC and 35ºC while cores are idle, and is very silent.
Note: In Brazil, during the summer.