Like many others, I too have several camera bags. As of now, I have an old LowePro bag that holds all my Nikon gear and a small bag for my Minota gear.
The Nikon bag contains my FM body, a 135/2.6, a 80-200/3.8, a stock 50/1.4, and a 28/2.8. I also like to have a couple filters and a vivitar flash included. As for Misc. stuff in there, generic rolls of 200 and 400, and a couple of reference cards.
The Minolta bag has my XG-A, 135/2.8, and a 50/1.7 with a J.C. Penney strobe. I also have a roll of 200 and a roll of 400 included.
In both of my bags I have a notepad w/pencil, an empty film canister, and a small Nylon bristle paintbrush for taking care of dust on the lenses.
I'm always looking for ideas and suggestions! (and cameras hehehe )