I definetly enjoyed the humor Ralphie brought to the show. Although he was such a scumbag, he was often hilarious.
His death came so suddenly too, it seemed like he and Tony had patched things up and were working togethor with the horse and everything, and then BAM, in one episode, he's dead. Big Pussy, while being a major character and one of my favorites, had so much build-up to his death you basically knew it was coming, it was almost dissapointing (almost).
But ultimately, I gotta say Ralphie.