Locking a ball for me has always been a very satisfying part of pinball.
Here are my favorites:
TZ - locking pinballs in a gum-ball machine...perfect.
TS - the magnet grabbing the ball and throwing it around the corner
TAF - The Thing hand coming out and grabbing the ball and the thunk the ball makes when going in the lock is hard to beat
IJ - The Idol is perfect theme integration
MET - the hammer lock under the play-field, into the coffin is great...when it works
TOM - the magnet on the trunk
CV - the lock for highwire is cool
GB - going under the play field and the sounds of the ghosts going in the trap and the light on the trap
What would be your list?