Location photo/laptop backpack, fully convertible, low profile - for great stability, good security - access to main compartment only if bag is off -shoulders, good durability - the main zip works with, not against the bag.
This is the basic model, for compact D-SLR and video kits and 12" laptops. E.g. EOS Rebel XT/350D, 30D, D70, D200 (w/o battery grip) & attached lens up to 10cm , 2 lenses up to 12cm long, external flash unit, compact DV cam or lens up to 20cm long and acc.