Hello,
There are many factors to consider like personal preference and equipment limitations. (A slow lens will limit your chances of "freezing" some action)
I am by no means an expert or a pro, not by the longest shot, but I like to use panning for fast action shots. The idea is to show the subject sharply in focus while blurring the background to evoke the emotion of movement.
But there is no right or wrong. I've done the opposite as well: Slightly blurred subject with sharp background will also convey "action" as well as freezing fast action. It also depends on the situation. Freezing a baseball in mid air about to be hit is a powerful image. By the way, I love ajtour's excellent shot of the tennis ball caught in mid air. But freezing a race car will simply look like just parked there. My suggestion is try all, take as many as possible and then decide which works best for you.
But most importantly: Have fun!
panning
These are point and shoot snapshots. Not the greatest but they illustrate what I'm trying to say...
slight blur
lame attempt at "freezing" with a point and shoot over a long distance in low light
Thanks,