Chazro, the size thing usually has to do with distance from the screen. If your TV is in your bedroom, you are probably viewing from a closer distance than normal, so the smaller size may very well be better. For those of us that watch in the living room from a much further distance, you might be very surprised at the difference the bigger screen makes, especially on the eyes. You can look up guidelines for screen size vs. viewing distance from several different great sources on the web. For my viewing distance of 9 feet, my 50" plasma is barely big enough. I used to view a 32" from that distance, though, and was amazed at how much easier it is on the eyes to watch with the bigger screen.
Another big factor is whether or not your 50" plasma has been calibrated correctly. After you have had it on for at least 200 hours, you should have it professionally calibrated, and watch the guy do it so you can do it yourself in the future, as I did. This was some of the best money my wife ever spent, let me tell you - it was a huge difference! Those things are calibrated initially so they look good in a salesroom - they look quite a bit different in any home environment, and need to be calibrated accordingly. I think the same goes for the LEDs, etc., but I know it is true of the plasmas in particular.
