It's rare they that just stop but it is pretty common to have problems. For example, Westinghouse are notorious for issues with HDMI handshake issues. It's also common to have dead pixels on LCD's. Another problem is that since each year they introduce new technology to the TV's they usually mess up something. An example of this is the 120hz that everyone is talking about that a lot of LCD's fail at implementing. This year it's going to be 240hz and internet connectivity.
That's probably the reason Westinghouse is at the bottom of Consumer Reports list. They aren't perfect, but that magazine is a great guide for most people.