There is no "best game ever". Such a premise would imply that all people are the same, which they are not. That's why I think the worst part of gaming fandom, by far, are the elitists who try to dictate what is and is not a "game".
Now, that being said, I think Chess is the most well-designed game I've ever played by far.
Regarding games like Pac-man, one of the negatives of the rise of the NES as opposed to the Atari generation was that, for awhile, games were generally memory based as opposed to reflex based. That means that once you learned a level, you pretty much mastered it. I remember reaching a point where I could beat every NES game I owned within minutes while barely paying attention.
My favorite game ever is Final Fantasy Tactics. I used to fire it up and run a level in Deep Dungeon any chance I had. I got every weapon, item, skill, and character. All my characters were max level, with all abilities. It was just a blast to play.
