Antec SmartBlue350, 350 Watt 6-Output, Dual Fan-Cooled ATX Power Supply SL350BLUE

Pros: high quality, low noise
Cons: high price

What is a power supply? A power supply converts electricity from its AC form to several DC f ...

Pros: stable, reliable, and very quiet
Cons: A little more expensive then other brands made by channel wells.

I believe antec has a company named Channel Wells to manufac. their power supplies. They make'em for other companies as well. The quality of the mosfets is amazing, they can take a high load and emit little heat. This means they're very efficient.
One of the nicest thing is the thermo-controlled fan on this specific model. Since the fets are so efficient and since antec fans in the fans, you won't have to hear the whinny noise of a generic fan. Even though the fan barely pushes any air, and it gets kind of warm, the stability of the voltages is rock hard.
Lastly the power rating. It says 350watts, but look closer. The amperage rating is well over those of a 420watt power supply. It can be a little tricky, but most generic power supplies tend to give more lower voltages then higher voltages like 12v, which you need the most these days. P4s for example, run mostly on 12v controlled by mosfets on the board. Newer, faster graphic cards also demand more 12v power. This power supply is upto date, and very reliable, i've been recommending it to friend since i first used one.