Looks like many of us in this forum are bitten by this bigger the better bug.
To share my story I started my search with 40/42, then quickly realized 46/47 would be just perfect even 50 wouldnt be a mis-fit my family room is 13.5 feet X 11 feet and the typical viewing distance is about 12.5 feet. With inputs from ever-helping forum members, I had set my eyes first on 47LH90 only to be informed that this was no more in production. I then tried for the Samsung PS50B550 only to find that this model was also discontinued. I then tried hard for the Samsung LA46B650 (which according to me is the best Samsung TV available in India) but I could only find 2 display pieces. By then I had auditioned almost all the available models 40 55 models and shortlisted LGs 2 models 47SL90 & 47LH70. For a brief while I even considered the LGs 55LH50, the only 50+ inch LCD that I found during my 3 months long search. However, considering the VFM (& the PQ I maintain that I found LH70s PQ to be greater than equal to Samsungs B550/530), I decided to take the 47LH70. But after the delivery and during the installation, I realized that this model (LH70) didnt have connectivity ports at the side and this was an important care-about for me as I connect my camcorder & the portable DVD player (with USB playback) to the TV very often. So I requested the dealer to replace this with 47SL90 and he agreed. Unfortunately, 47SL90 was out of stock and I was made to wait for weeks. After about 3 weeks of wait, I learned that LH90 was back in stock, but only 42 models were available. After thinking hard it was only about size vs. PQ LH90 was always my 1st choice in terms of PQ I settled for the 42LH90.
While I am very happy with the 42LH90 I still yearn for a bigger screen. I had even called the dealer (just about one week after the delivery) asking him if he could get either the 47SL90 or 46B650 or 55LH50 and allow me to exchange the 42LH90 (to which he politely declined)! Today if I manage to get a very good offer from someone (from this forum??) to sell the 42LH90, I may do so and go for a bigger screen (though I am not sure which one)!
Actually for my distance, watching TV programs - including live sports (which is what I spend time watching the most) and movies that appear full-screen (English movies, old Hindi movies) in a 42 screen (especially in LH90 with such great PQ/ customizable PQ settings), is just perfect. It is only while watching movies - from DVDs or through USB where the cinemascope screen shrinks the picture I really feel I should have a bigger screen.
Maybe it is this quest/urge for a bigger screen that will keep us interested in tracking all that is happening in this product segment