Trenken,
I think that you should really try to check out the 37D40U before taking that plunge. I have seen some good reviews on the 37D40U, but I have also seen some reviews similar to my own "despite praises from sites such as LCD_TV_BUYING_GUIDE at the showroom this TV isn't as impressive as others". This is what caused me to go out and see for myself, and I agreed with that assessment.
Now since my post from last night, I read the entire 37D90U thread in this forum - and based on that and other reviews (cnet, others), I am settling towards that one. It seems like there are other reasons to get that TV other than the fact that it is 1080P. It seems to do a lot of other good things as well - and actually, 1080P won't hurt us: our kids will be using this for video games, and how often do kids playing video games sit back the reccomended distance of 8-10 ft? No, they will be viewing from 4-5 feet, and in this regards, 1080P will help us. (someone did report in that thread that side-by-side, the d90u looks better than the d40u).
Having said all this, I now owe it to myself to find a D90U to see in person before taking that final plunge.
Finally, with the online prices, the d90u is only about $300-$400 better than the d40u.