I would go for anything that really captivated me, regardless of genres.
I usually give up instantly if the game does not get me from the start,
so these games might not be the run of the mill mindblowingly good games.
But any game that I feel compelled to finish deserves a spot on my list.
Abe's odyssey/exodus
Grim fandango
Fallout 1 and 2
Sid Meier's Alpha Centauri
Master of Orion II: Battle at Antares
System Shock 1 and 2
Farcry
KotOR
Sins of a Solar Empire
Planescape Torment
X-wing vs Tie Fighter
Nethack
AvP 1 and 2
And for games that don't really have an ending.
World of Warcraft
Heroes of Newerth, prefferably DotA but that's a mod so meh.
Team Fortress 2
Wesnoth
Dwarf Fortress
I usually give up instantly if the game does not get me from the start,
so these games might not be the run of the mill mindblowingly good games.
But any game that I feel compelled to finish deserves a spot on my list.
Abe's odyssey/exodus
Grim fandango
Fallout 1 and 2
Sid Meier's Alpha Centauri
Master of Orion II: Battle at Antares
System Shock 1 and 2
Farcry
KotOR
Sins of a Solar Empire
Planescape Torment
X-wing vs Tie Fighter
Nethack
AvP 1 and 2
And for games that don't really have an ending.
World of Warcraft
Heroes of Newerth, prefferably DotA but that's a mod so meh.
Team Fortress 2
Wesnoth
Dwarf Fortress