I chose "Kyle's Mom's a Bitch" because I believe this movie has what I think is peak Cartman. He's just teasing Kyle, not abusing a girlfriend or causing someone great pain. He's relatable, teasing his friend because he has a "bitch" of a mom, something guys tease each other about. Bigger, Longer & Uncut basically remade the song from it's original appearance in "Mr. Hankey, the Christmas Poo" and improved on pretty much everything. I love it, and it's what I think of when South Park songs are brought into conversation.