I use a Swiss Army Shoulder bag/briefcase pack that has a handgrip, a removable messenger type shoulder strap, and optional tuck away padded backpack shoulder straps. I've used it for the past three years in all three modes and found it quite comfortable and versatile. I've packed it with an extended use EDC, my laptop, and file folders to where it weighs maybe 40-50 lbs at times and been able to move through the streets of Manhattan and the subways and trains on daily commute just fine.

Sadly, I do not remember the model designation, nor does it appear that SA carries that model any longer. Glad I grabbed mine when I did. For urban carry, it can't be beat.

I used to use a smaller Everest messenger type bag (not with the big flap, but with a top zipper and front pockets) for my EDC, but now that I find myself traveling more and having to tote my laptop, the SA is a must. The shoulder srap mode is decent for daily carry, and the backpack straps are more suited to longer excursions afoot or where I really need to keep both arms unencumbered. I don't necessarily like carrying backpack style during urban commute because I can't see my pack when in a crowd and I've already caught one SOB getting in my bag that way. Fortunately the cops got him before I could.