Here's mine:
Room for 1-series with 70-200 2.8 mounted, 24-70, 16-35, flash, spare batteries.
Filter and card pocket. Somewhere inside.
Separate small personal item pocket. (Organizer for keys, etc)
Laptop sleeve up to 17".
Room for books or other stuff, think enough to fit say three full 3" binders.
Clips on shoulder straps for camera or telephoto lens case.
Padded hip strap.
Modular attachment system of some sort.
Bottle compartments on both sides with straps to hold tripod and monopod.
Rain cover.
..This bag would be enormous.





