Doesn't appear to be too many of us here with the 40in. We would have loved to have gone larger but we had to settle with the 40in, as it was the largest we could fit in our media chest. It is replacing an old JVC 32in tube. Ours came one day last week and I wish I could give you some settings but I have not been able to play with it much. Took me a number of days before I got it out of the box. So far I have had only limited viewing using and old HD DVD player and Amazon Instant. I hope soon that I will be able to get it in the media chest and hooked up to the direct tv box and a blu ray player. So far I really like it! I don't have much to compare it with though. Our other 2 flat panels are a 50in Samsung HP-S5053 plasma and a 21in LG LCD and they are both getting on the old side (circa 2006/07), but still work great.
I think what I am going to do is try some of the settings that have been suggested for some of the larger ones and see what happens. I have played with a few of the settings but cannot remember which ones. As one of the poster above mentioned the sharpness needs to be set low. I found this also to be the case. When I get a chance to really fiddle with it I will try and post back.
I have the 55" and I like it so much I was thinking of getting a 40 or 32" for my daughter.