What is the quietest power supply that you have personal experience with?

Or, what is the quietest you consider noteworthy? I have a pretty nice computer that I purchased second hand, and then upgraded. It is a nice, clean, roomy LianLi case with an ASUS A8Ne MB. The power supply is a 420 watt, of pretty good quality, and leaves me a good margin of safety. I'm sorry, but I don't know the brand. I did extract it once, googled it, and was satisfied, based on its specs, that it was a good quality one. My computer has an Opteron170, 2gigs of low cas latency ram(2x1gig sticks), 3 harddrives-a 74gig WD Raptor(SATA), and two WD EIDE Caviars. The video is a BFG 7900GS with 256 megs, that has it's native, stock cooling fan. The motherboard chipset is also cooled by a small fan. The Opteron has a Zalman fan with a rheostat control. As I don't overclock, I empirically backed off on the RPM, downloaded a utility that tells me the cpu is running nice and cool. There are two DVD drives, and a Creative Labs X-Fi sound card. In addition to the CPU, Video, and chipset fans, there are two 120mm case fans. I perceive the fan noise to be coming mainly from the back, so I went to FRYE's and bought a 14dba 120mm fan and replace the rear one, whose specs stated that it was a 34dba animal-brand name ADDA, a dual bearing desgn. The fan replacement made no difference in annoying noise level. There is no grinding, rubbing, etc,. just more noise than I want to live with. Any suggestions on quieting this otherwise good machine down? I'm pretty sure that, based on where the noise is coming from, the power supply is the culprit.
I figure anything in the 350 to 600 watt range would do, but above 400 would be best. I've heard Antecs are quiet, but I can't find any reviews that point me to a good one.
Any opinions?
Thanks.

 

I always used Antecs until I fitted one of these about a year ago and I now use nothing else. They have a speed control on them that when turned right down make them very quiet. Case fans are also always a big problem and I recommend these, as again you can turn them down till they are near silent. I would bet your graphics and chip fans are major contributors to your noise.

 

I think you need to make a definitive call that the noise problem is definitely coming from your PSU before you buy anything.

PSUs are way down on the list of "noise-makers" in PCs if they are functioning correctly.

 

Fan Noise

I have an old X86 with upgrades, originally made in 2000. The unit sounded like a Huey landing in a hot LZ - variable noise, bearing rumble. Case fan not running. Replaced the PS with an ATX noiseless 450 - little change. I decided to tackle the CPU fan. It had play in the blades and was an obvious culprit.

Unfortunately, finding a match for a 754 socket was not possible without delay. So I found a matching frame in a Masscool with the same width and mounted it onto the old CPU cooling tower. A three pin power socket was necessary, another compatibility issue.

Fortunately, everything matched without MB replacement and I am now riding a 747 at 30,000 feet.

Can not wait to try Arie's recommendations with another upgrade.