LCD's are generally brighter and have a better real world contrast ratio. Plasmas do suffer from burn-in, whereas LCDs do not. Burn out is not the problem it use to be with plasmas, life spans are virtualy the same between the two technologies. Picture sharpness goes to plasma. LCD's are cheaper. The cheaper plasmas have poor color recreation and a smaller viewing angle.
My vote....LCoS. Not cheap though. But you get the benefit of both with none of the drawbacks.
