nightcraw1er.488: That's really impossible to say. At every stage of life new things appear which are influential, there was a dungoen crawler on the acorn at school, and granny's garden on the nimbus.
Baldurs Gate 1/2 I have played many times over the years. GTA 1-Vice City were classic. As well, it depends on genre, I agree with several of the posts above, Thief, Morrowind, Warcraft 2 was pretty good. No-one mentioned Doom yet?
Ultima 7 was a game I spent weeks on, still have the paper with each town mapped out.
The list is endless.
Can you post a pic of the paper with town maps? I would love that.