Av most of the time. M when i want to do long exposures or when i use flash. And P when i need to take a quick pic with flash that doesn't look too bad.
the P mode on my camera is pretty smart for the average scenes. Then sometimes I'll have to shift the program or exposure compensation. Actually, I think that at parties, and when I need to be very quick, I'll use P.
But on my outings, I'm using M.
Av generally as I tend to shoot wide and fast, events, people (they tend to move about too much). Manual for times when I just got lots of time on hand to compose and try different exposures.
Back to the camera modes ... When I go shoot shoot with friends, I use Manual Mode. ;p
And if I'm driving with the camera on my side, Popgram mode <--- no time to fiddle with the settings when shooting things that fly across my windscreen :bsmilie: