Here are mine, with the logic behind them (5D3):
External speedlite control: to control flash on or off, mode, curtain, manual strength. Very useful with ETTL triggers.
Expo comp: bracketing, HDR, EV
Custom controls: for switching on/off back-button quickly when handing to other people (better than green box IMHO, especially if i have settings dialed in with flash)
LCD brightness: not the best pick, since auto is fine, but nice to have the option for playback
Custom shooting mode: awesome for setting a scene on the fly. I rarely set my Custom modes permanently, and if i did, i'd forget what mode is what (and different lenses may make them irrelevant). I usually set an ideal C mode for flash, and one for shooting wide open. It's nice to set the wide open one to shoot with the external flash disabled, so that i can go from flash to wide open with one twist of the control dial rather than the multiple steps involved in changing via manual controls (turn off flash, adjust ISO/shutter/aperture)
ISO speed settings: for limiting Auto-ISO ranges in specific shooting conditions and minimum shutter speed.
honorable mentions: Image quality, Number of Bracketed shots (for 3/5/7 HDR), Highlight alert (blinkies sometimes bother me).
(T2i/550D has a function for "Shutter/AE lock button" which directly addresses back button focus. Also has an "ISO Auto" function for max ISO)
External speedlite control: to control flash on or off, mode, curtain, manual strength. Very useful with ETTL triggers.
Expo comp: bracketing, HDR, EV
Custom controls: for switching on/off back-button quickly when handing to other people (better than green box IMHO, especially if i have settings dialed in with flash)
LCD brightness: not the best pick, since auto is fine, but nice to have the option for playback
Custom shooting mode: awesome for setting a scene on the fly. I rarely set my Custom modes permanently, and if i did, i'd forget what mode is what (and different lenses may make them irrelevant). I usually set an ideal C mode for flash, and one for shooting wide open. It's nice to set the wide open one to shoot with the external flash disabled, so that i can go from flash to wide open with one twist of the control dial rather than the multiple steps involved in changing via manual controls (turn off flash, adjust ISO/shutter/aperture)
ISO speed settings: for limiting Auto-ISO ranges in specific shooting conditions and minimum shutter speed.
honorable mentions: Image quality, Number of Bracketed shots (for 3/5/7 HDR), Highlight alert (blinkies sometimes bother me).
(T2i/550D has a function for "Shutter/AE lock button" which directly addresses back button focus. Also has an "ISO Auto" function for max ISO)