Also, on the RROD, the newer systems have been modified to minimize this. There shouldn't be as big a problem with this in the new "Falcon" models, which have a 175w power supply. Those have become standard for anything manufactured after October 2007, I believe.
For those with an older model, some of the suggestions I've heard are keeping your power supply off the floor, buying a cooling unit, etc. I have no idea, though, because I was lucky enough to pick up a Falcon model at a decent price.