My favorites include:
"We're going to France! We're going to Italy!"
"Don't I get any change?" "Please, stay the way you are."
The Michael Bay shot as Dangeresque draws his nunchuck gun following the death of Dadgeresque.
But the top for me has to be...the Poopsmith in a wig. Strong Bad's inability to get through his lines when talking to/nunchucking the Poopsmith parallels my own struggle to keep from giggling to myself every time I worked on something with him in it.
I'm having trouble deciding between episode 4 or 5 as my personal favorite, but this was definitely my favorite to work on.