I got my Thunderbolt on launch day and I just got my wife one last week and when I put them side by side the new ones display has a grey tint to it. All the white areas in the display like in the clock widget and the keyboard have a grey tint.
So I took the new phone to the store and compared it to the two floor models and the one the girl who helped me has and it was the same thing a grey tint.
The rep went ahead and replaced it and the one she replaced it with was the same way. So we figure that the display on all the new generation Thunderbolts are like this because her phone and the two floor models are launch day phones as well as mine.
I don't know if anyone has noticed this or not but I thought I'd share.
If you have a Thunderbolt that came out close to launch day compare it to a brand new one that someone has just got and you'll see what I'm talking about.
Or if you've just got one go to a VZW store and compare it to one that came out on launch day.