I have the R102 which is everything except the extra slot to carry a computer. It's a tough backpack, comfortable and doesn't really scream "Hi, I am a camera bag, steal me at the earliest convenience."
http://www.amazon.com/Kata-KT-R-103-GDC-Rucksack/dp/B0009PYV6KWith that, I am about to upgrade to the Think Tank airport rolling bag as it would better fit my stuff and is what I would bring on location for planned or paid shoots.
I also have a Lowepro slingshot which is ok for just a camera and couple lenses, but it gets uncomfortable after hiking with it. It's more of a lighter weight walk around city type bag.