Plasma has a superior picture, the new 8th and 9th generation screens have a 60k hour life expectancy, the color separation is better on plasma and the blacks are blacker. If you are looking at Costco the Panasonic HD 50" is a very good deal, and you cannot beat Costco's warrantee. If you read any of the AV forums the Panasonics are generally considered the best for a decent mid level HD TV. The latest 50" Panasonic is the the TH-50PX60U, the 42" is is the TH-42PX60U, the previous generation have a 50 where the 60 is.