I just wanted to come back for the benefit of the fence-sitters, and say that I purchased the Samsung LNS4095D this weekend, hooked up Comast HD Digital Service, and I am officially in love.
I had been concerned about black levels on this model, both from posts on this board, and from seeing the model in the store. It boasts a 6000:1 contrast ratio, but I felt like the Sony 40V2500 (7000:1) contrast ratio was doing a much better job with blacks during my in-store comparisons. When a found a few adjustments in the settings, my opinion on the Samsung's blacks changed entirely. I did this by first switching out of the store-default "Dynamic" mode, and going to Custom.
Then, the three major steps were:
1. Turning off DNIe (big difference here)
2. Turning Energy Saving to Off or Low
3. Turning up Brightness in the settings.
HUGE difference!! Suddenly the Samsung was doing what I thought only the Sony could do. I had always thought it was a shame that the 4095 couldn't handle blacks because I thought it made colors POP. After these adjustments (and tinkering with the other picture settings) , I unquestionably preferred the picture of the LNS4095D to the 40V2500. (It's still no XBR, but then again, what is?)
My other major concern had been what SD would look like. SD Digital channels are lower quality than my old tube TV, mainly because they look blurry. However, this is a SLIGHT blurriness, and it in no way keeps me from watching or enjoying SD channels. As a point of reference, I consider the Mitsubishi LT37131 to be unwatchable on SD. The only thing that keeps me off SD is how AWESOME HD looks on this set. Abosolutely ridiculous.
Anyway, both the Samsung LNS4095D and the Sony 40V2500 are great great sets. I loved them both in the store, and I thought they each had advantages and disadvantages. But I was able to resolve (by my own standards at least) the major disadvantage I felt the Samsung set suffered - black levels. From that point on, I was sold on the vivid colors and SLICK looking cabinet.
My friends and family have all been blown away by the set, and yesterday I watched the best looking football I've ever seen. Maybe best of all, I'm ready for 1080p! I can't say much more about the 40V2500 than you've seen yourself in the store, but I'm happy to cast one BIG vote of confidence for the LNS4095D.