Any service calls you'd process through the manufacturer anyways unless it's something that goes wrong in the 30-day money back guarantee of the retailer. 
 
I agree with Dan, the LCD will weigh less, and will also use substantially less power.  Plasma's are power whores and use quite a bit of power. 
 
Almost forgot, I'd wait till we get closer to the holidays, LCD prices are going to start falling like crazy.