My Custom Settings And Preferences

Lets start by saying that my custom settings have evolved over the last few years and changed with the various camera bodies that I have had,
Canon 30d, Canon 5dmk2 followed by a mk3 and currently a mk4.
Again I must stress that there are no wrong and right settings its all about what works for the individual.
The mk4 has some really nice custom settings available, nearly all the buttons can be re-programmed to suite an individuals photography needs, I do like to keep it as simple as possible though.
Seeing as I mainly shoot birds and wildlfe I have my settings tweaked to make life as easy as possible for me out in the field, I need to be able to switch from a static bird setting to a Birds In Flight (BIF) setting at the drop of a hat.
In order to achieve a BIF setting at the drop of a hat I have set C3 up as my goto BIF setting a quick press of the button and a spin of the selector and I am at C3, you might ask why not use C1 as you dont have to spin the selector so far, well being an old git I cant remember where any of the settings are but I do know C3 is the last one so I can turn the selector without looking at it and know for sure that I am going to hit my BIF setting everytime, sometimes you dont get a second chance, if you mess up its over in a flash and the opportunity is gone.

 Bearded Tit

Canon 5dmk4 @ 700mm 1\400th f8 iso200

OK my basic BIF settings are set to TV mode 1\1600th, Auto iso with an upper limit of 800, +1ev, AI Servo AF, High speed continuous, I can quickly change the shutter speed and adjust ev if required but the above settings are a good place to start for me.
I also have Case 2 slightly tweaked selected for BIF, I always shoot with white balance set to "daylight" and picture style set to "Faithful", as I always shoot in RAW most of these can be tweaked in post processing.
One thing I was shown when I first got my 30d was to use the "AF-ON" button setup to back button focusing, I have used this ever since, on the 5dmk4 however you can customise this button and the "AE Lock" button, and whats more you can set up a whole host of  other settings on these buttons which can transform the ease of moving from spot AF for sitting birds to AF Expand for moving birds.
I have the following custom Settings:
Shutter Button set to "Metering Start" Only

AF On Button Set to "Metering and AF Start"
In The AF On Sub Menu I have set the following:
AI Servo Characteristic = Case 1 Versatile Multi Purpose
AF Operation = AI Servo
AF Area Selection Mode = Spot AF

AE Lock Button Set to "Metering and AF Start"
In The AE Lock Sub Menu I have set the following:
AI Servo Characteristic = Case 2 (Tweaked) Continue to Track Subjects Ignoring Possible Obstacles
AF Operation = AI Servo
AF Area Selection Mode = Expanded AF

 Cock Linnet 

Canon 5dmk4 @ 700mm 1\400th f8 iso200

So for a bird perched I use the AF On button to aquire focus using spotAF to get accurate focus on the area of the bird that I want, and then shutter button to take the shot, if I release the AF On button I retain focus on the bird this acts as one shot AF.
If the bird decides its had enough and flys off I switch to AE lock button, I then have a larger area to obtain focus, it also switches to case 2 in the AF characteristics to help me keep focus locked onto the bird.
I think Canon missed a trick here they should have given the option to also set the shooting mode and relevant shutter speed and or aperture.
I hope that all makes some sense, please feel free to comment and open up discussions and add your own suggestions.