Tough call--
my personal favorites are
AIDS walk woman: you HAVE to wear the ribbon! Kramer: you know what you are? a ribbon bully. *walks away*
Newman complaining about the radar detector not working, to which kramer replies no no, i don't think so, muchambo.
also more or less any time he leaves the room with an inaudible verbal gesticulation. like when he eats the 2 double-fudge sundaes after realizing that his love for Pam may never be fulfilled, and elaine notifies him in monks that jerry and pam's relationship isnt going to last because he isnt gaga. kramer leaves with "ga-deh!" or something... weird wild schuff.
anyway, im rambling.
anyone else?