For everyday "just in case a picture pops up in front of me and needs to be taken" carrying around, I don't take as much with me as I'd need in order to really feel prepared. There's at least a tripod (currently two tripods and a monopod) in the trunk of my car, and I always have a body and lens with me. The lens is usually a 50 or 85, sometimes the 35-105/3.5, rarely the 70-210/4, and last night it was (unusually) a 24mm. If I have a hunch that I might need a couple more options I'll bring a second lens along and/or a flash. Which body I carry depends on which is closest to the door, which already has film in it, which I feel I haven't used enough lately, and pure whim. It's usually a K-mount, but the Spotmatic and the older screwmounts come out to play sometimes too.
If I _plan_ to be shooting, it's a different ball game. There are four approaches I can take depending on what shooting environment I expect to be in, how portable I have to be, and what gear I expect to need: 1) Throw two to four bodies and six or seven lenses in different lengths (including a zoom or two) into a haversack. 2) Hang one body off my shoulder and grab the "everything but the really long lenses and unusual stuff" bag. 3) All my K-mount gear and maybe the Spotmatic, in two bags, with a couple of screwmount lenses and the M4->K adaptor in there too. 4) Both main bags plus the case of screwmount gear (including bellows), the Nishika 3-D camera, and if I'm feeling paranoid, the Konica A3 as well. -- Glenn