The lack of overhead space has already been alluded to in this thread. I have a camera backpack which has my DSLR, three lenses, flashgun, spare batteries, spare SD cards, a portable hard disc, laptop, various batteries and chargers and still has space for a book, light waterproof and one or 2 other bits.
So far, I've always managed to get it on board except on an Embraer 145 in the USA but then I had the laptop in a sleeve and the camera back pack has the camera in a removable insert. So they came out and went on board with me, the "rest" of the pack went in the hold, gate checked, and all was good with the world!
In terms of packing any, or all, of this gubbins so that it can be checked I would buy one of these
Peli Products UK There is the theft issue but I came across someone in the US who used a Peli case and he took the view that the case, even in a plain vanilla version, stood out to a degree that shouted "steal me and face the consequences". Do I agree? Not sure. But he flew frequently, always with the case, and claimed never to have had a theft problem with that case. If the carry on rules are strictly enforced my camera back pack is going to be refused in which case the Peli seems to be my only solution (short of leaving stuff behind).