There's a few PWM 140mm Phantek fans on sale. These are highly rated, and push a good amount of air for the noise they make. Some people prefer these to the Noctua, and Thermalright fans.
Phanteks PH-F140MP_BBK_PWM, 500- 1600RPM, Frame/Blades 140mm, Radiator Fan, Black
They also have the rounded 140mm fans on sale.
Phanteks 140mm CPU Cooler Fan Upgrade, PWM, 1600 RPM High-Static Pressire, Blades Retail Cooling PH-F140HP_BK2(II) White $15) /Black $10.43)