I usually take a rucksack, which I put the laptop and camera into, and then take my tiny little Tinkerbell bag that I picked up from
WalMart a few years ago. I fill up Tinkerbell with all the little awkward bits - keys, UK purse, US purse, liquids, etc - so that the larger, regular shaped stuff goes in my racksack. Generally speaking, I don't need anything in my rucksack for the flight, just what's in my Tinkerbell bag, which works out handy, since it means I don't have to go wading through and disrupting everything.
My laptop has one of those foamy skin things, which I used the first few years, but now I just tend to chuck it in my rucksack without anything. Also takes up less room, since the foam cover is reasonably thick!

Obviously, laptop has to be taken out at the airport and repositioned (which can take a few minutes), but that's about it.