This bag is great. It easily holds my baseball setup:
1 20D body, 1 XT body, 1 70-200 f/2.8 L, 1 300 fixed prime f/2.8 L, with hood, 1.4 extender, 17-135mm USM IS lens, 22mm USM, 1 battery grip, 4 extra batteries, memory cards, cleaning kit, and Manfrotto Monopod. (I just stick it in one of the loops for easy access) You cannot beat the price and it's an unassuming backpack. (Doesn't scream "I have expensive stuff in me!") Also takes a beating. I did get the zipper stuck on the flaps that cover the zipper area. That was a pain, but was able to extract, by snipping the cover area very slightly
Overall a great bag.