@consagra- you're right, the 42 "B" models were notorious for their noise. some other owners reported noises in the 50" as well...seems to be symptomatic of Samsung's entire "B" model.
@nitti48- i was lucky and received the newest 50" plasma, PN50C450. unfortunately, i got a buzzing unit. got my fingers crossed on the replacement. kinda sad that these tv's aren't 1080p, but they still look good for a "free" tv.