I'd hate to see what you paid for that thing. I have a 50" Hitatchi Plasma in my bedroom and it makes no humming/buzzing sounds at all. There are many fans on a plasma and being a 63" they may be more of them or may be louder though. I know that on my 55" LCD in the living room, the fan will run for 60 seconds or so after you turn it off. Does it only make noise while it's on?
My phillips buzzes a little but you have to be behind it to hear it.
I have a 50 inch and it puts out a good amount of heat. Can't imagine how much heat a 63 inch puts out!
I have a 50 inch Pioneer Plasma (top of the line in Plasma TVs) and a 42 inch Panasonic Plasma TV. Once you go Plasma, you never go back. :) And I don't have any heat or buzzing issues people are talking about. Of course my Plasmas are on TV stands and not on the wall, so they might have a little better air circulation.