apart from default, read the manual and set the following custom functions:
ISO expansion: on (allows to use ISO 50, 12800 and 25600, I think 12800 is still acceptable)
Use extended AF points: on (enables those hidden AF points around centre point, not sure why it's disabled as default)
AF point selection method: multi-direction joystick (this is personal preference, I think this makes choosing AF points much quicker)
set Flash sync speed to "My Menu". it effectively is the Slow-sync setting which should be easily accessible.
also set Mirror Lockup to "My Menu", very useful feature taking long exposures on tripod.