I picked up one of the 51" versions a little over a week ago, my first HDTV, believe it or not! I had an old but nice 27" Samsung CRT, and to be blunt none of the less expensive LCDs looked as good as my CRT, resolution aside, and the recent price dropping of plasmas is what finally kicked me into getting one. I was planning on getting the 43" version, but the 51" was on sale, so it was only $70 more. Glad I did!
I've spent most of the last week tweaking the settings among my various devices. I read everything I could find about calibration and fine tuning, took some advice that goes against what I wanted to do (and the advice was correct) and fiddled, fiddled, fiddled. I still don't have the settings for my cable box quite where I want it, but the game systems and bluray/DVD movies look excellent. Some friends told me to shell out the extra cash for the 1080p model, but I'm on a tight budget and I've always cared more about accurate color reproduction than resolution anyway.
One thing I like about this thing is that it saves the different settings for the various inputs, it lets me tinker to my heart's delight. Here's what I'm using currently, but I'm always tweaking:
Cable box or PS3 playing movies through HDMI:
PIcture Mode: Movie
Cell Light 20
Contrast 87 (I keep tinkering with this)
Color Space Auto
Color Tone Warm 2
All options set to off
Video Games through HDMI (PS3, Xbox 360, etc)
Game Mode: On
Picture Mode; Standard (can't change in Game Mode)
Cell Light 20
Color Space Auto (Note, Native seems to look better in certain games, but it's really oversaturated, not accurate)
Color Tone: Standard (Warm1/2 just doesn't look right in games in my opinion)
HDMI Black Level: Low
All options set to Off
A note on HDMI Black level: The TV supports RGB levels, and the PS3 have options to support it, but I find that the expanded values on the game systems (expecially the 360) to be wrong, causing both systems to crush blacks. Also, the 360 may automatically detect the native resolution of the TV as 1024x768 and switch the TV to PC mode, but I can't get it to look as good as 720p mode with the above settings.
It was also hooked up a SNES through the component input, and was pleasantly surprised that the scaler in the TV made it look pretty good. Not as good as a SDTV, but still pretty good. The NES didn't fare as well, but it still did better than expected. I ordered a composite/s-video to HDMI scaler/converter to see how it does.