This is all personal preference, but in the very early days, there were still some enormously good games. The Crowther-Woods "Adventur" game was ground-breaking in its ingenuity, and of that type, I don't think Level 9 ever issued a bad game. I still remember "Lords of Time" with a distinct degree of fondness - and remember, you could play these quite happily on a computer with only 48K of RAM and no more than tape storage. I never got access to a computer big enough to have a serious go at the early versions of "Zork", but I devoutly wished for more than the half-hour that I managed to wangle. And you should never forget "Atic Atac" either.Some of the platform games like Magic Miner were pretty good too, although personally I didn't like that style of game. The ancestors of the present day role-playing games were around shortly afterwards. I had a lot of fun out the "Rogue"-like low-graphics game Moria.
Moving on from there, the early high-graphics adventure games were pretty good before people began to run out of ideas. Space Quest 1-3 and Kings Quest were all pretty good before people began to run out of ideas and the games got silly. Then came the heyday of the single-player RPG game, of which IMO Might and Magic III and Eye of the Beholder 2 (Legend of Darkmoon were among the best)
Then came the internet, and the MUD (multi-user dungeon) games. I've never been fond of these. In my experience, there are too many wreckers around, whose primary aim is to attack other players. So there you go.