In a way...this is a difficult list to make...

1-Season 16
2-Imaginationland
3-With Apologies to Jesse Jackson
4-A Ladder to Heaven
5-Mr. Hankey's Christmas Classics
6-Cartoon Wars
7-Canada on Strike
8-Raising the Bar
9-The C2 Trilogy of Season 14
10-Starvin' Marvin
11-The Succubus
12-Prehistoric Ice Man
13-Trapper Keeper
14-Christian Rock Hard
15-Awesome-O
16-All About Mormons

Honorable Mentions...

The Passion of the Jew
Death of Eric Cartman
200 and 201
Summer Sucks
Terrence and Phillip April Fools Special
Cartman gets a Probe
Chef Aid
Korn's Groovy Pirate Ghost Mystery