Firdea recently suggested adding support for a presentation mode which I thought was a good idea.
However, there seems to be little consensus amongst well-known apps of how this ends up looking.
Visual Studio 2012: Hides toolbar and title bar and all docked tool windows (menu and status bar remain)
Firefox: Hides everything and then reshows tab bar when cursor is moved to the top of the screen
NotePad++: Hides everything but document tab bar
Word 2010: Offers 'Full Screen Reading' that hides everything except a mini toolbar
IrfanView: Hides everything
My preference would be to hide all 'bars' except the menu bar, leaving the app fully functional in every way, just maximising screen space.
Obviously this can be controlled by preferences but I'm still interested in hearing what you like to see when an app is in full-screen mode.
Dan