Favorite Messenger Bag?

I'm looking for a new messenger bag for my 15" MBP. I need something that will easily hold the power cord, some pens, phone, and maybe a couple of books. I'd also prefer to have a handle on top, too, for those times when it's easier to simply grab the top and carry as opposed to slinging it over my shoulder (such as pulling it out of the overhead compartment when exiting a plane).

Durability is key for me as well.

What bags have you been pleased with?

I have this one - and overall have been quite pleased with it. Thule 15" Crossover Messenger Bag - Apple Store (U.S.) My only slight wish list for improvements would be - more places for pens (because I'm a nerd and very particular about what I write with), one additional divider and a thicker carrying handle as I tend to carry it like a briefcase just as much as I do slung over my shoulder.

It's been great for air travel though. The lay flat feature is a must have in any bag you choose so you don't have to pull your MBP out.

It's not a messenger, but I'm really pleased with my Benthaven Metro Lite bag. They have a core protection system with hard side walls, a spring loaded mechanism at the side to keep the laptop from shifting, and lots of little thoughtful touches like a pouch for your iPhone/iPod with a cutout to thread your headphones through. The quality is phenomenal too.

This is their messenger bag - it's a little pricey, but I'm sure you could find it cheaper elsewhere...
Switch Messenger Bag - Blk GI Jo/Controller | Brenthaven.com