Lately we've been leaning towards Enermax supplies for our higher end systems. A good supply to benchmark potential choices against is the EG365P-VE (FCA) model. This is a 350 watt design with dual fans, plenty of connectors for extra drives inside your PC and it's extremely quiet. Enermax markets the supply as "Whisper Quiet". I don't know if I would go that far but in our system our SCSI drives made a heck of a lot more noise than the power supply with both fans operating and high speed. The system has 3 IDE drives, 2 Ultra 160 SCSI drives, 2 optical drives and several PCI cards. Everything is rock solid and the Enermax is quiet.
In another system we installed a Seasonic Super Silencer 300. This is a nice unit that makes very little noise and is designed to consume less power and create less heat than competing power supplies in its class. This is an excellent choice to quiet down a computer in the home that's on all the time. After we installed it the fan blowing down on the heat sink of the microprocessor inside the PC was making more noise than anything else. This supply uses a rubber surround that provides additional dampening between the fan, case and power supply. It's not quite as heavy duty as the Enermax design but can handle plenty of computer without a hiccup.
Ironically, the last three power supplies we've replaced have all been Antec supplies. Some go bad quietly but often times there will be a pop and a puff of smoke. A power supply going bad can be a dramatic event. The good news is it's one of the easiest things to replace. And it really can make a big difference in performance and reduce the noise pollution of your PC making it easier to live with.