I think my favorite line is when everyone is in court and the verdict is recieved by a lot of "Oh no!"s and such, when as random as hell, the Kool-Aid guy busts into the court house and goes, "Oh yea!" then backs out and runs away.
Me and my friends imitate that all the time.
I also prefer the scene when Brian and Stewie go on the Germany tour, and Brian and the Tour Guide argue about WW2.