"Can you get rid of the extra canvas background you added in cs3? I don't understand the need for yet one more setting to toggle through when hitting the f key. And it's slower! Let me turn it off plz."
In Photoshop CS4 and CS5, we eliminated this extra Screen Mode and went back to the 3 Screen Modes available in versions of Photoshop prior to CS3. Users can optionally include the 'extra canvas' (Application Frame/Background) by enabling Window>Application Frame.
Additionally, you can save key presses to get to "Full Screen Mode" directly by adding the shift key when hitting the f key to cycle through Screen Modes in reverse (Shift + f).