i'm upgrading components in my dell studio 540 tower. i figure with everything i'm adding a 500 watt PSU should cover the load. i went to Frys to pick up a Corsair tx 550m (which was $61 but is now $79) but the guy i spoke with talked me into buying an Antec earthwatt 650 for $69. i'm all for saving the earth and some money if i can, but do you think it is a comparable trade off? if not, any recommendations?