First Click: Backpack or messenger bag?

I need a new bag for my computing stuff. Ok, not need per se, since I have an embarrassing number of bags already, each capable of carrying my laptop and camera gear and whatever else I might choose to hoist over my shoulders. But none of my bags are perfect. My defect is that I’m certain I’ll find a better bag if I just keep looking. Question is: should I get a backpack or messenger bag?
I grew up in Ohio, a state responsible for establishing trends related to presidential elections