I actually voted for episode 4.
Then I read this thread, and remembered the Ewoks.
I change my vote to ep 6.
Ewoks.
Don't mess with them.
Those little teddy bears will kick your ass UP THE YIN YANG.
Also, because of this:
From p12 of "STAR WARS - The New Essential Guide to Vehicles and Vessels":
The page on the AT-ST (Imperial All Terrain Scout Transport Walker)
"AT-STs will no longer be deployed on planets with an abundance of trees or other known obstacles such as rock-wielding primitives." -Excerpt from the Imperial AT-ST manual, updated shortly after the Battle of Endor.
That's right, even the empire says not to piss off the little fluffy dudes.
[size=10](Also, because I'm a stickler for details, technically the book should have quoted the update to the manual as saying "celestial bodies", not "planets", seeing as how Endor is a moon, not a planet)[/h]
Top that, General Grievous.