I have been through quite a few airports in the last few months. I think that Detroit Metro is pretty cool. I have heard that it used to really suck. They have done a lot of work to it apparently. There is a tunnel that connects the terminals. The tunnel is dark, but has a light show on both sides of it, with music. It is really worth walking through it just to check it out. Somebody was thinking when they put that feature in. Also, in the main terminal, there is a very nice fountain that does some pretty cool things with water jets.
Also, I think that Memphis is a pretty nice airport. It is not really crowded (with the exception of Starbucks), and you can find a place to sit.