I agree with you on Sony is overpriced. BY THE WAY, the KDL40EX700 (the model in UK is EX703, it has great reviews) is a LED tv. Anyhow, I will look into Samsung LCD/LED. In terms of plasma, I read many articles now, and also compared in the store side by side between a Panasonic VT25 (3D model) vs a Samsung LED (8000 model? both top 3D models), Panasonic Plasma wins hands down. Wondering why you felt Plasma is not good at all. Apparently Plasma had some improvements in the last two years, may entice some buyers to reconsider.
As for that particular salesperson, another reason I recommended him is because he told me all the TVs he himself have tried and why he felt Plasma is better. He reminded me of myself, when I was younger, all the bad computers I have to go through, that make me a better computer geek. There is an old Chinese saying, "If you always get sick, you become a better Doctor".