I was playing around with Exposé in Snow Leopard, because I really like the new algorithm (or whatever they did to change it to make it look better).
I had my cursor hovering over a window and I hit the Space Bar, and the window zoomed up, just like using Quick Look on a document in Finder. This also works when using the arrow keys to select the windows.
I can see the benefits of this for if you have a lot of small windows that look the same, or if you just want to take a quick glance at a window before proceeding to another one.

