Isn't it ironic that all those modes were introduced to simplify camera operation and save time, but now one has to spend a lot of time thinking about what would be the appropriate mode for a given situation...?
When I walk around, I have my digital camera set to P for no-hassle, quick response. (On my film bodies, I use aperture priority or manual, because that's all they can do.) As much as there is to be said in favour of aperture priority, I frequently experience that if there's enough time to decide on a specific aperture, there's also enough time to go completely manual.