I've really been enjoying the Parker Brothers games for the Atari 5200. So far I have Q*Bert, Gyruss, Mr. Do's Castle, Frogger II, and Star Wars: The Arcade Game.
I like their 2600 games, too. "Star Wars: Jedi Arena" has been a longtime favorite, and "Q*Bert's Qubes" is the one I want to get to know next (I have a repro).