I am using several versions of the Lowepro Topload Zoom bags including the AW version that I like quite well.

They are just big camera cases, not full fledged bags. Tougher and better I believe for the camera. They wrap around the camera and are well designed to prevent damage from both weather and shock and bumps.

I am not a big fan of backpacks alone. I use them to carry optional lenses, battery chargers, filters, flashes, etc. but I prefer other carrying options. Daybags doubling as a camera bag or vice versa don't seem to work for me. Besides, every new camera needs its own case for protection!

Whatever you choose, write a review and let everyone know how it works for you!