Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

I used to have a Crumpler backpack (King Single) and I can say that the quality was top notch.

However, it wasn't designed very well. It lacked practical functionality.

Can't comment on messenger bags. I tried them but backpacks are much more functional. After going through many bags (Timbuktu, Crumpler, BBP) I've settled on the Herschel Pop Quiz and couldn't be happier.
 
for my 15'' rMBP I use this:

Timbuk2 D-Lux Laptop Messenger Bondage, Black/Black/Black, Small
http://www.amazon.com/Timbuk2-Laptop-Messenger-Bondage-X-Small/dp/B004IC1GFE

It's supposedly designed for 13'' computers, but the rMBP is so thin that it fits in this bag. the fit is snug, but it does slide right in. it's a great relief, since going to the 15'' size would mean a much larger bag.
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.