I really like this bag. It's the Kata DR467i. It can be expanded with different Kata bags/gear and there is a place on the back where you can easily connect a trolley.
There are three main compartments: one for the computer (which easily fits a 15inch and I think could fit a 17 as well); and the other two are a generalized top compartment and a divided lower compartment. There is a divider between these two and it can be removed by unzipping. I really like this backpack because it is super light, has plenty of space for the size, and can be made to fit whatever you are trying to carry. I also like to have my computer sometimes when I go on short trips so that I can dump out my memory cards and look at my pics.
The bag also has a rain cover which has come in handy a couple of times.
All in all it is a very comfortable bag, with tons of options and it's so light that I actually like using it.
I don't like any other kind of a bag for my cameras as backpacks are the best at leaving my two hands clear and comfortable for shooting and they don't hinder walking or running.
Also, I have two op/tech shoulder holsters which I attach across my chest in X-formation. One GF1 dangles from my left, and one dangles from my right. The two don't dangle too much and allow me to have two lenses with very fast easy access.
Loopit is another strap that people seem to like. I couldn't get one in time for my recent trip (even though the loopit people were quite nice and tried to help me out as much as possible) so I went for the op/tech. But the loopit seems to be smaller and better for GF1 sized cameras (although I haven't actually tried one).
All in all I really like my kata, and the op/techs work fine; although you need to purchase op/techs smaller "mini qd loops" ($6 for set of four) for a easier fit into the GF1's tiny brackets.