*Do not* lay plasma screen flat!!!
Plasma screens cannot be laid flat. Simply laying one down flat for more than a few minutes is sufficient to crack the internal screen. Something about the gases, I'm really not sure what causes it, but I work in retail, and I know as a matter of fact that just as sure as one gets laid down flat, it's done. Couldn't tell you how many I've seen come back because of this. And you can always tell what caused it, because it specifically cracks the internal glass (the external glass usually remains intact). Trust me, you don't want to lay one down.