I shoot in raw only because it's fun to develop my pictures myself. But I am an amateur and have enough time to do that. Efficiency is not as important to me as it is to professionals.
Professional photographers use whatever suits their purpose best. Time is money and thus professionals are very pragmatic. It's mainly the amateurs who demonize shooting jpegs. Sport photographers, for example, need a high frame rate and quick results and therefore they shoot jpegs. Several other photographers like Bob Krist shoot jpeg and raw. Bob Krist, who is an excellent travel photographer, uses mainly the jpegs out of the camera and develops raws only when needed. If the jpegs out of the camera are good enough, professionals will be much more willing to use them than many amateurs.
Raw on most cameras. While shooting with cheap pocket cameras, I shoot jpeg but set the resolution one notch below maximum (eg. on a 12 megapixel Canon IXUS 105, I shoot at 8mp resolution), which usually gives better noise performance and a better idea of how a large print of the image would look.
Raw, generally. Better detail retention and more flexible dynamic range, for an array of PP options. Last night I was processing some Sigma DP2s pictures and ended up with some in color and a few in B&W. Raw gives that kind of flexibility. Also, I like a certain look, and I often find that OOC JPG settings don't allow me enough flexibility to tweak and customize to get that look in camera.
JPG is lossy and you're just throwing out data that could otherwise be leveraged. But that's me. If I was a pro and had the inclination I would absolutely learn my camera and understand how to get quality OOC JPGs to be more efficient.