Update...
I checked out the iPhone 4 display units at the AT&T Store over lunch and both of them look like my 3G--brighter with true blues. The manager even agreed with me that the screen didn't look quite right. Guess I might try to exchange this one.
Your 32GB looks like every other 32GB I've seen; I'm willing to bet all the demo models you saw in store were 16GB models. They have a much better screen than the 32's. I'm on my second 32GB and it looks just like the first; however, my girlfriend's 16 and every other 16 I've seen looks great.
Go figure, you pay more for the top of the line model and get an inferior product.