If viewing distance is 2.35m, I suggest you to buy no smaller than 50". If you think it is too big, you will be fine after one week later, as I am using 50" plasma in 3 room and viewing distance is 2m and even my wife don't find it big at all . Make sure the screen is not too reflective.
Just think about watching movies in the cinema screen size to your sitting distance ratio.
Hope this helps.