I received the Silenx 450 Watt 14 Db power supply today. It was a piece of cake to install. Just comparing weights between this supply and my old ones was a good indication that it is a lot better.
It is certainly quieter than my old one but there is still lot I could do to make the PC even quieter. For a start the fans are blowing against crap old grills that not only restrict the air but the turbulence causes a lot of the noise. I also have one really noisy 20Gb IDE disk which will be getting yanked at some stage and replaced with something a bit more sociable.