This is a page to help you calculate your power needs:
<A HREF="http://www.jscustompcs.com/power_supply/" target="_new">Power Supply Wattage Calculator</A>
And Toms has an article written in January that reviews about 15 PSUs.
<A HREF="http://www6.tomshardware.com/howto/20040122/index.html" target="_new">http://www6.tomshardware.com/howto/20040122/index.html</A>
For an example I'm using the 400w Vantec Ion with a floppy drive, four hard drives, three optical drives, 1x120mm fan, 3x92mmfans, and 1x80mm fan. I've had this for awhile now with the adjustable fans set below maximum and have had no problems.