As for power supplies, you will probably want one that is labelled as 80 Plus
http://www.80plus.org/.
They generally cost a bit more. I think I paid an extra $20CDN over a generic power supply for an Antec EarthWatt 380W. It was on sale though.
The 80 Plus power supplies don't use as much power and won't heat your house. They are a minimum of 80 percent efficient compared to the 70 percent efficiency* of standard power supplies.
* This is an estimate. I'm not sure the accepted number is, but I'm sure it is around 70%.