What to wear on one's shoulders to interviews? (bags, backpacks, etc.)
I have seen them in all in faculty job talks in our department for the last few years. I have seen messenger bags, backpacks and briefcases; some of them have been made of expensive leather and looked really classy/professional and I have even seen them made of cheap, fraying materials.

Either way, it does not matter - except maybe in incredibly conservative departments. We hired one of the folks who had a pretty cheap looking backpack. The fact that he/she had multiple publications in the top journals and conferences in their area probably mattered more. They were all wearing suits though.