One of my personal favorites is "Copland." Prior to the release of the movie, Stallone became a caricature of sorts. After Rambo and Rocky in the 80s, his movies were just cliched and awful (although I think "Cliffhanger" and "Demolition Man" were OK).
But Copland really showed his acting chops and made him more human. He should have done more dramas and maybe even a romantic comedy in the 90s, rather than action and underdog-type movies.