7800 Asteroids is such a good port. I still play it despite owning a real cabinet. 2600 Asteroids is probably the game I have played the most in my life - my bro and I CANED that game for at least a year....I doubt a day went past when we didn't play it.
7800 Centipede is a brilliant port too - and like Asteroids on 7800 - has some excellent 2 player simultaneous modes.
Berzerk on 2600 is maybe the best arcade port on that console. Just a pity there were no diagonal shots from the robots though.
Memories of 2600 Decathlon. My bro and cousins wore out joysticks on that in 4 player mode - so many memories.
I think I prefer Beamrider on 2600. The 5200 was such a mis-step for Atari. They never really recovered.
2600 Joust played well but the 7800 port was great - really solid feel to it.
5200 Kaboom! - What was the point of that with no paddle control? It does have an interesting 2 player mode where player 2 controls the bomber but with no proper control it's a mess.
2600 Megamania - another game I caned. I completed it (it stops at 999999pts).
2600 Missile Command was a real surprise to me. I though it would be crap but it was translated really well. Atari devs really were craftsmen back then. Vies with Berzerk for best port award.
Space Invaders - I wanted this game SO MUCH back in the day. I didn't get it until years later when the shine had worn off but it's a great cartridge on 2600 - mainly because of the excellent 2 player modes inc. some co-op games.
Enjoyed 2600 Space Shuttle - was mind blowing what the 2600 could be coaxed into doing.
Super Breakout - 2600 version every time. Paddle controls. Simple as that. It's a great port of the game - I still play this.
Super Cobra - had this as part of a long term swap with my cousins. Played the hell out of it but that jerky scrolling was headache inducing. The 5200 port looks really good but never played it.
2600 Vanguard was a good game but the absence of background tunes made it feel empty. And the final boss was so disappointing - a single hit kills it - when I realised that the longer you dodged bullets and held out before killing it the more points you got then it felt better. Played it a lot.
Jr Pacman on 2600 is a great game - really solid port. Rock hard though - it's an accomplishment just to beat level 1....