Depends on a lot of things. What use? TV or monitor? If monitor, from how far? Are those prices from the same store? Did you check their ratings on ResellerRatings.com?
For $1280 I would pick the 42" any day. It's a good price. But that is just me, with my needs and uses for a monitor---dunno about you.
About 75% monitor and 25% 720p or higher TV. Distance could be whatever.
Prices were from two equally reputable online stores. Think 9.5+ on resellerratings (Newegg-ish).
Yeah it was a good price on the 42" but I'd rather spend significantly less money. Also the 42" would cost even MORE to ship back to Westinghouse if there is a problem.