I'm gonna put my bid in for Roseanne (i think its more of a 90s show--it ran from 1988-1997)
come on, how can you turn away a sitcom about a lower middle class white family, complete with a daughter-switch, gay grandmother, daughters with white-trash-esque boyfriends...
and then the show JTS (jumps the shark) when they win the lottery and go all willy-nilly.
jump the shark - if you really wanna know exactly when your favorite show went downhill