My biggest problem with all these courier/messenger/mail bags is the way the shoulder strap is mounted to the bag. Most are those cheesy snaps. I've been running a laptop for about 8 years now and have had a couple just let go.

I needed a new bag last year and looked and looked for something that did not have the cheap connections. Found this:



Perfect! Wide, thick strap riveted to the bag. Big enough for a laptop, papers, power cord, and some food! Friggin love the bag

Here's a link to one place:
http://www.luggagepoint.com/lpProductDetail.asp?productId=6801

"Never underestimate the power of human stupidity" - Robert Heinlein