The 90s, hands down. Going by U.S. release dates, here's some of the notable games released in just the first half of the decade:
1990: Super Mario Bros. 3, Mega Man 3, River City Ransom, Batman, Double Dragon II, Final Fantasy, Super C, Ninja Gaiden II, Castlevania III, Dragon Warrior II, StarTropics, TMNT II: The Arcade Game, Phantasy Star II, Thunder Force III, Strider, Castle of Illusion starring Mickey Mouse, Shadow Dancer: The Secret of Shinobi, Bonk's Adventure, Splatterhouse, Legendary Axe II, Devil's Crush, Valis II,
1991: Street Fighter II, Super Mario World, F-Zero, Gradius III, Final Fantasy IV, Super R-Type, UN Squadron, ActRaiser, Super Ghouls & Ghosts, Super Castlevania IV, Sonic the Hedgehog, Phantasy Star III, Streets of Rage, Turrican, Rolling Thunder 2, Mega Man 4, Battletoads, Ninja Gaiden III, Bonk's Revenge, Ys III, Fatal Fury
1992: Mortal Kombat, The Legend of Zelda: A Link to the Past, Contra III, TMNT IV: Turtles in Time, Super Mario Kart, Super Star Wars, The Magical Quest Starring Mickey Mouse, Axelay, The Legend of the Mystical Ninja, Soul Blazer, Sonic 2, Golden Axe II, Steel Empire, Streets of Rage 2, World of Illusion, Ecco the Dolphin, TMNT III: The Manhattan Project, Dragon Warrior III & IV, Valis III, Gate of Thunder
1993: Doom, Star Fox, Super Turrican, Batman Returns (SNES), E.V.O., Super Empire Strikes Back, Secret of Mana, Super Mario All-Stars, Lufia & the Fortress of Doom, Zombies Ate My Neighbors (both SNES & Genesis versions), Disney's Aladdin (both SNES & Genesis versions), Sonic CD, Lunar: The Silver Star, Thunder Force IV, ToeJam & Earl in Panic on Funkotron, Tiny Toon Adventures: Buster's Hidden Treasure, Rolling Thunder 3, Mutant League Football, Rocket Knight Adventures, Shinobi III, Kirby's Adventure
1994: Super Metroid, Mega Man X, Final Fantasy VI, Donkey Kong Country, Breath of Fire, Illusion of Gaia, Super Punch-Out, R-Type III, Earthworm Jim, Sonic 3, Sonic & Knuckles, Castlevania Bloodlines, Contra Hard Corps, Mega Turrican, Killer Instinct
The latter half of the 90s had some good ones, too, though I always felt the transition to 3D was a rough one. The N64 had great games like Super Mario 64, Mario Kart 64, GoldenEye 007, Star Fox 64, Banjo & Kazooie, Super Smash Bros., and Blast Corps. The PS1 had Final Fantasy VII, which was the entire reason I even bothered getting a PS1 in the first place, and it had other games for it that I enjoyed (at the time, at least), including Resident Evil 2, Einhander, Mega Man 8, and Colony Wars. And the SNES kept getting gems like Chrono Trigger, Super Mario RPG, and the Donkey Kong Country sequels in its later years.
There's a reason why I look back fondly at this time period.