How about a backpack suggestion?
I've been looking for a year or two, for a smaller-than-usual *backpack* to carry around my laptop (now it'd be my iPad) - the whole issue with backpacks is that they're made to hold lots of stuff, right, so you can imagine it's hard to find a small, minimal backpack.
All I'd want really would be a main pouch big enough for something ranging from the iPad up to maybe a 12" laptop, and an outer pouch for accessories or gadgets. Alongside the iPad I may additionally carry a BT keyboard, but the iPad will be itself in a folio case in the bag. And as flat as possible so the iPad isn't flopping about in there.
What say you!?
Messenger bags and anything with a cross-sling strap I'm not a fan of. I like going one-shoulder with a backpack, it's more comfy to me.