In the drop-down box, make sure 'All Applications' is selected, then add Enter Full Screen and assign CMD-F to that.Go down to Application Shortcuts on the left, click the + sign.Open System Preferences > Keyboard > Keyboard Shortcuts.So keep that in mind, and adapt the ensuing instructions as you see fit). (EDIT: Like the complete knucklehead that I can be, I forgot that CMD-S is frequently used in many apps to 'Save' a file.
So in thinking of 'Find' as 'Search', and logically associating 'S' with that function, and 'F' for 'Full-screen', I have my solution! What doesn't appear to be frequently used is CMD-S.
Well depending on the app, 'Search' is used interchangeably with 'Find', and both are generally bound to CMD-F. I'd rather use CMD-F, but that's bound to 'Find'. In general, I just dislike using 3-key combos, but almost always prefer a keyboard combo over clicking a button on-screen.
One thing I don't like though is using the default key combo CTRL-CMD-F to toggle it on/off. I'm slowly getting to like the full-screen mode for apps in Lion… something I didn't expect to happen.