I have this guy ^^^ ... and it has been absolutely amazing for so many situations. Bought about a year ago or so and has traveled on a skate trip in Tokyo, another trip through Europe, and just random US jaunts. Though it is LowePro, it doesn't send a red flag to people that you are carrying a crap load of expensive equipment as the logo is pretty hidden. It fits my Panny GH2 with 3 lenses, filters, extra batteries, cleaning kit, extra cards, and a few other trinkets in the bottom compartment (you do get crafty with it). The top compartment is nice for additional items you want to bring along (GoPro, wallet, passport, whatever). Finally the back has a little slip for additional slim items. I found this perfect for maps and transit times/such.
One of the final sells for me is the all-weather cover. This thing has been through some serious rain and my gear has yet to be harmed even the slightest. And in case you are wondering, I have managed to fit a "cam caddy" and standard tripod on the pack as well.
Hope this helps.