How to pack...
TL;DR: legal size carry-on bag *plus* a 'personal item' is a laptop bag for small laptop and endless gadgets.
If I'm going on a trip, I'd bring several gadgets, including a small laptop. The airline allows a 'personal item' which is a full size laptop bag. Modern gadgets are so small that the laptop bags easily holds a small laptop plus another half dozen gadgets (incl several tablets) and accessories. It all fits into one laptop bag 'personal item'. Even full size noise cancelling headphones of the folding variety.
Ladies with handbags can't have another laptop bag, sorry.
The legal size carry on bag is for clothes and such. Nothing tech or valuable just in case the carry on bag needs to be 'sky checked' at the aircraft door.
This method allows essentially unlimited gadgets, and a carry on bag just for clothing.