UDG Ultimate ProducerBag Large

It's quite simply huge. The laptop partition is big enough for a 17" laptop and the remaining space is large enough for all of my spare cables, headphones and power supply.
There are pockets everywhere and room for everything including the kitchen sink.
As for the quality, it's what you would expect from UDG, I have several of their bags and they last forever, taking any abuse you choose to throw at them.

This is my second UDG backpack. Roomy and durable. I fly often, so I want to be sure that the equipment is well protected.