Finishing many of the missions would be impossible without force jump. So that one's indisputable. Same thing goes for force pull and push. As for the other "involuntary" powers, I like force speed.
Now, as for the ones you can choose to develop. I'd have to go with force heal.
I don't get the popularity of force grip. I prefer mind trick. Here's an example of why. There are enemies and an automated gun sentry around the corner. With fully developed mind trick, you convert an enemy in the room into an ally -- and the gun mount starts shooting him.
Walk up to the gun mount and blow it up with a saber toss.
Mind trick is particularly effective on "flying" troopers and other heavily armored ones armed with disruptor guns.
At more advanced levels, force absorb renders most dark jedi virtually powerless.