I’ve got a lowepro slingshot 200AW. It holds my gripped D80, 50mm, 18-55mm, 50-200mm, 70-300mm, 105mm, lens baby 2.0, SB-800, charger and two extra batteries quite well, and the pack itself is not huge, especially considering all that it can hold. The main downside is that there is no place to attach a tripod, although I might be able to with their sliplock system. I like how easy it is to access the camera, and the safety snaps that keep the top from opening all the way accidentally are nice too.
I bought it at Costco last Christmas for around $55, and couldn’t be happier with it.