When do you use each and how often? It's tough to say for me, as I seem to use AF more than I used to, but always still finding myself in situations where I use manual focus. I'm definitely more split down the middle than someone who always relies on AF. When I do more serious work, I always tend seem to MF.
I use autofocus for:
General photography, snapshots, family shots
Sports / Action
Some street photography
I use manual focus for:
Portraits
Street photography
Macro
Still life / abstract
Landscapes