I fully agree with carrying a camera with you in case something catches you eye, but (and this is "for me"), if I'm heading out to do some "serious" photography, I have to have an idea of the images I'm looking for if for no other reason than to carry the appropriate equipment along (if I'm shooting wildlife, no need to lug around macro equipment - not to mention a completely different tripod). It also helps me if I have an idea of the type of image I'm wanting - otherwise, i just get caught up in the environment trying to look for everything and anything, that I'll wind up missing the finer details and images that I'm actually looking for. (Now, if THAT made sense, then I need to take up English as a second language :^)