I think that the category might be wrong, so feel free to suggest a better one
As I recently got a surface book, I want to invenst in a semi-decent carrying option that can also hold some other shit while not being as annoying as a backpack. (other shit = powerbank, surface pen, A4 paper, pencils and shit, (in ear) headphones, surface charging adapter). And the thing should be somewhat water resistant, as I dont want to buy a dedicated surface protective case thingi as well
It might start some awkward conversations if you aren't into DnD, but the bag of holding from thinkgeek is actually a seriously good bag. http://www.thinkgeek.com/product/aaa5/?srp=1 50 bucks but goes on sale pretty often, usually like 30-40 percent off. Back when I had to carry textbooks I was able to hold a semester's worth in there, but don't do that because it's terrible for your back. I've had it for about 4 years now and it's still going strong. I've been caught in the rain with it before and nothing inside ever got wet; it's made of canvas so it'll absorb water but not let any through. They have some variants like a backback version and a leather version if your interested in that.