Unlike Majid, I've had good luck with Timbuk2 bags, enough so that they're always one of the names at the top of my list if I'm thinking of a new bag.
At CES this year, I carried a 17" MacBook Pro around (along with adapters, headphones, a Canon S90, and a bunch of other things that made for a heavy bag) pretty much everywhere I went, and the Timbuk2 Breakout Messenger was extremely
comfortable. I was afraid I was going to pay a heavy price in back and shoulder pain for not going with a backpack, but the Breakout Messenger (using its very cool sling strap
) worked just as well for me as any of my backpacks, in terms of comfort (and earned points for greater gear accessibility, without having to take the bag off). (The Breakout Messenger also comes with a standard shoulder strap, but I never use it.)
When I travel, I even pack a netbook into the Breakout Messenger with the MacBook Pro (along with its power adapter), and that makes for a very heavy load (for a messenger bag). Still, I find the it comfortable, considering the weight.
The Breakout Messenger isn't perfect, however. The hand strap is not padded, so I use it only as a grab strap, and not for carrying. The main non-laptop compartment doesn't zip open far enough on one side for me, and I find this makes it a bit tougher to insert and extract folders and papers, especially when the bag is being worn. Also, there is no water bottle holder.
Currently, the Breakout Messenger is my main office-on-the-go bag.
I have other Timbuk2 bags, and appreciate them all, including a rather small messenger bag I use with my netbook when I don't need the bigger laptop.