I leave all of my games set on 3 ball. 5 ball games just seem to last forever, and kill the competitiveness when you're playing head to head. Especially if you're playing an AAB EM, or a modern pin where you collect extra balls.
Now some EM's can be set to 5-ball, mainly because of short ball times. But modern games on 5-ball? Seems a little overkill and takes some of the fun out, especially when setting or trying to beat high scores. At least in my opinion.