The sad fact for me, is that most manual modes besides the oldschool scale-matching systems are actually more confusing than liberating.
I use aperture priority 90% of the time because I don't have any cameras that have what i consider a good manual mode. A good manual mode is either a match-needle setup like the Canon AT-1/Olympus OM-1, or a match-LED setup like the Pentax LX. With a manual mode this good, there is no reason to use aperture priority mode. IMO many manual modes on auto-exposure cameras are tacked-on and too slow for anything but tripod use. LED scales (like my Nikon F801), numerical "+/-" readouts (Pentax Program A), or having to press buttons to match the meter (as on the Pentax ME Super) is too slow and just doesn't cut it. Even the F100's meter readout is too fiddly for me, despite the fast aperture and shutter dials. So on most of my cameras (which are mainly Pentaxen) I use aperture-priority mode, plus the very quick-to-use exposure compensation dial. Most of the time I'm using a Pentax ME, in which case it's aperture priority+exposure compensation, or nothing.