Ye old Dock: Leopard-style Exposé under Snow Leopard
OS X minitip
Samuel Clay shares an awesome little tweak: replace Snow Leopard's Dock.app by the Dock.app from a beta version of SL, and Exposé will get back to the way it acted on Leopard, i.e. the size of the thumbnail is proportional to the size of its window.
And it rocks.