Solaris for the Atari 2600. Came out very late (1986) so nobody played it but it's one of the best, if not the best game on the console. I can also see
Pitfall! is not there.
NES:
Crystalis.
SNES:
Secret of Mana. Sim City (favorite version of the game)
Yoshi's Island.Gameboy: Final Fantasy Legend 2. Final Fantasy Adventure.
Gargoyle's Quest. Gameboy Advance: Mario & Luigi (Not the 3DS version!) Metroid Fusion.
N64:
Blast Corps.
Banjo Kazooie. Mystical Ninja Starring Goemon, not a great game but has tons of charm.
PC:
Sim City 2000.
Half-Life.
Civilization 4.
PS1: FF7. FF Tactics. Symphony of the Night.
PS2: Ico (Better in standard definition). Katamari Damacy. Valkyrie Profile 2
PS3: Dark Souls. Spelunky. Pixel Junk Shooter 1 & 2. I would say Red Dead Redemption, but playing it recently.. the magic was gone.
Gamecube: Metroid Prime. Pikmin or Pikmin 2. Paper Mario Thousand Year Door. Resident Evil 4? The Wii version's too easy. Haven't played the other 998 versions.
Wii: Mario Galaxy 1 & 2 (they have merged into one in my head). Kirby's Epic Yarn.
Wii U: Super Mario 3D World
Arcade: Outrun (driver's seat version). Teenage Mutant Ninja Turtles. Marble Madness
are we ignoring obvious classics like Super Mario Bros.? Why is Snake, Rattle and Roll there? It's good for an isometric platformer but essential?