My favorite episode is the one where Robert meets a pretty girl, but pretends that he is Ray Barone. Raymond didn't mind as he lived vicariously through his brother. The final scene when the girl showed up at Raymond's house and mentions to Debra , Frank and Marie that she was dating Raymond after meeting him in a bar.
Some of the episodes with Amy's family are classic. An episode that didn't work for me was the Italy trip. Frank and Marie were real homebodies, who had a major problem with even going to a nice restaurant.
I'm in the minority. I think Marie Barone is the best character on the show.