Been there, done that. The "Google PC" is nothing more than a typical competitor to what's already there. The Wal-Mart maneuver is going to be a bad one because Wal-Marts are already being actively boycotted due to their Juggernaut marketing practices. I can just as easily stick to the Fry's Electronics "major name brand" computer made by GQ for $179. It runs Lindows out of the box and comes with the basic keyboard, mouse, speakers, and necessary media.
I feel the "Google PC" is going to be a big flop and will only be a hit among those who use gMail. Even then, most of them will realize, they can get the same quality for less; elsewhere, but will end up buying a decent laptop anyway. Perhaps a smarter move would be to purchase Microsoft.