Really, you should be using the ball rating system established by (I think) a spam bot in off-topic.
So then...out of 8 balls...
SW - 7 balls
ESB - 7 balls
ROTJ - 4 balls
TPM - 4 balls
AOTC - 2 balls
ROTC - 3 balls
TRM - 10 balls (projected)
And yes, I actually like TPM about the same as ROTJ. *shrug*
Incidentally, I've seen fanedits of the prequels that easily add a couple balls.
EDIT: Definitely a spambot.