I really wanted to vote for the SNES Donkey Kong Country trilogy... but I went with Perfect Dark instead. Honestly though, I love every game listed.
The reason I chose Perfect Dark was because it was the first game that I really played a lot of with friends. Every day after school we'd hop off the bus and run straight to my house to play some Perfect Dark on the N64. We put an ungodly number of hours into that game, and loved every second of it.
Whether we were beating up simulants or gunning each other down, there were always three certainties: One, my parents were going to tell us that we should play outside since it's such a beautiful day. Two, we were going to have a blast without going outside. And three, Kyle was inevitably going to knock over someone's drink with a controller cord.