SPCR

The following are some of the PSUs available to me locally. Which of these are known to be quiet and reliable? Thanks...

Antec High Current Gamer HCG-620M
Antec High Current Pro HCP-750
Antec High Current Pro HCP-850 850W
Corsair CMPSU-650AX 650W
Corsair CMPSU-650HX 650W
Corsair CMPSU-750HX 750W
Corsair CMPSU-750TXV2 750W
Corsair CMPSU-850AX 850W
Corsair CX430 V2 CMPSU-430CXV2
Corsair CX500 V2 CMPSU-500CXV2 500W
OCZ ModXStream Pro OCZ600MXSP - 600W
OCZ ModXStream Pro OCZ700MXSP - 700W
OCZ Z Series 850W Modular OCZZ850M
OCZ ZT Series 550W OCZ-ZT550W
PC Power & Cooling Silencer Mk III 400W
PC Power & Cooling Silencer Mk III 500W
Seasonic Platinum-860
Seasonic X-760
Thermaltake TR2 Power 600W W0388RU
XFX Core Edition PRO750W

Seasonic.
Corsair AX is build by Seasonic basically X series.
All Seasonic built units on your list are semi-fanless, gold rated up to (when the inside of the case isn't too hot) 20% load, platinum 30% load.

The Seasonic PSUs would definitely be my first choice from that list. I'm not actually sure I would have any second choice.....

Seasonic, but the wattage is nuts - maybe the shops could be persuaded to get a lower wattage model? Corsair AX and HX as a second choice, stay away from the CX and TX.

The PC Power & Cooling Silencer got discussed recently, viewtopic.php?f=6&t=64974, but I have no personal experience with the brand.