Processors....

[redwudz]

One of my video server computers has eight PATA hard drives and a DVD burner, six 80mm fans, along with two PCI IDE controllers and a LAN card and runs fine from a good quality 450W power supply. The video card is minimal and the CPU is a 65W AMD. The exhaust air from the PS stays about 30C when it's been running a while. The startup current for the drives must be fairly high, but it's still running with no problems a year later.

The higher power drawing hardware these days is usually the CPU and the graphics cards.

[TBoneit]

redwudz, Exactly. These days everybody seems to believe they need huge power supplies. I had a customer that bought a 900Watt power supply off of the internet. He had 2 optical drives, 2 hard drives a floppy, a P4 3 Ghz, and a $80 video card. He didn't think he had enough power with the old power supply, 550Watt.

Todays new CPUs and drives use less power than previously and run cooler too.

For those that like green?
Get a motherboard that can use a mobile processor = less power consumed. Use Laptop hard drives = Less power than a 3.5" drive. Use built-in Video, sound, ethernet. One optical burner. My guess is you can get away with well under a 200 watt supply. Less speed too of course.