Quietest 120MM AIO?

I'm looking for a quiet 120MM all-in-one liquid cooler to put in my Node 304.  My current motherboard doesn't allow for large air heatsinks without killing airflow direction, so hence my decision for a watercooler.

I currently have a Seidon 120V with a Noctua NF-F12.  The pump's really loud, and is still audible even when undervolted.  I'm looking for a 120mm watercooler that has a quiet pump and isn't too expensive. 

Easy. Corsair H60. Have one in my Node 304 and it's nearly silent with the fans running on the low setting on the case fan controller. I'm also running two Corsair SP120 performance edition fans in push/pull. The pump is completely silent and performance is excellent. 

Should be able to find the H60 for $50-60 or less. 

I have a thermaltake aio thats been the most silence aio i have had. While it may be the orientation( its on some gpus)  i have found it to be more silence than anything from corsair. I really have not noticed any pump noise( Its in my small linux build) To me, the pumps are more robust than the corsair. Snoop some forums. Mind you the fans just suck: bring your own!

Any of the newest generation Asetek pumps should be the quietest. I believe they have the largest RPM range and the lowest threshold for pump speed which should lend itself to really low noise.