Tweaking your Exposé settings may not be the only requirement for getting full functionality out of your keyboard shortcuts in FCP and FCE. If you use the snazzy new aluminum keyboard (or are thinking about it), check out this article from Apple on Application-specific key functions with the aluminum Apple Keyboard. Certain media keys and newly-labeled keys on the aluminum keyboard “may seem to replace the functionality of certain application-specific function keys, such as the F10 function ‘Overwrite Edit’ in Final Cut Pro and Final Cut Express.”

The quick fix: Modify your settings in System Preferences>Keyboard & Mouse.
The quicker fix: Use the Function modifier key (Fn) while pressing your Function keys. (How is this different from how the current MacBook keyboards work?)

(Photo: Apple Support site)