After several bags with broken straps, I went to find the toughest bag I could.

I bought the 5.11 Tactical Briefcase. Wow, never going back to anything else.

The top is a dual-zipper with straight handle opening to a cavernous interior. I can easily pop out my laptop, pop in a jacket, it's gigantic. Two smaller outer pouches with slots for pens, key clip, the usual. Big flat back with divider (but the velcro gave out quick). Over the shoulder and fully loaded, it's comfortable. And it has the carry handle slot, of course. But that big easy-open center is unmatched by anything else.

That's all I want to add. Good ideas here otherwise.