"I'm not sure I will do the one bag thing again after I head home. I do like having stuff easily reachable in a messenger bag rather than having to think about the things I want to take out of the bag to have with me before I sit. It is however nice to know it can be done easily when it needs to be done."
I like the idea of one bag travel, but even on rather short flights I like to be able to have handy enough small things (snack, book, pen / notepaper at the least) that a 2d, smaller bag is hard to give up. It's also convenient to have a bag I can keep in front of me / in sight / sometimes locked up by itself with the most valuable things in it.