Your TOP games by GENRE:

Shooter:
1.CSGO
2.Call of Duty 4
3.Battlefield 3

RPG:
1.Ultima 7
2.The Witcher
3.Kingdoms of Amalur

Adventure
1.The Secret of Monkey Island 2
2.Zak mc. Kracken & The Alien Mindbenders
3.Quest for Glory

Casual
1.Hero of the Kingdom

Here's my list:

• Adventure: The Curse of Monkey Island
• FPS: Battlefield 3
• Racing: Race Driver: GRID
• RPG: Baldur's Gate
• Stealth: Splinter Cell
• RTS: Starcraft 2
• Fighting: Street Fighter II Champion Edition
• Platform: Sonic the Hedgehog

from my favorite genres

Role Playing Fantasy Game (single player) : Witcher 3
Role Playing Fantasy Game (MMO): Guild Wars 2
MMO - non fantasy: EVE Online (thanks for ruining my life love u CCP)
Role Playing Action Game: GTA 5
MOBA: LoL

Turn Based Strategy: Civ 5
Turn based Adventure: Baldur's gate

Simulation/Tycoon game: Prison Architect

Something to add:

Best rage: EVE Online
Best horrible community of scammers and trolls: EVE Online
Best good community with friends for lyf: EVE Online
Best politics simulator: EVE Online
Best economy simulator: EVE Online
Best spacerock mining simulator: EVE Online
Best spreadsheet simulator: EVE Online
Best lagging out a server with 2000+ players on grid: EVE Online
Best spaceships made of ductape and scrapmetal: Minmatar Online
Best game with a monument dedicated to it in reality: EVE Online
Best serious business: EVE Online

FPS: Half-Life
RPG: Borderlands
FRPG: Elder Scrolls and The Witcher. Okay, I like Torchlight too
Tycoon: Pizza Tycoon and Theme Hospital I had so much fun time with these gems.
Racing: Need for Speed II and Burnout Paradise

Shooter: CS:GO
Racing: NFS Underground
RPG: Pokemon
Indie: Bastion
Open World: GTAs
etc

Shooter: Battlefield 3
RTS: Company of heroes 2
RPG: Witcher series , 3 being the best.

RPG: Pokemon... Gold/Emerald/Mystery Dungeon Red Rescue Team
Open World: Mafia 2/SIMPSONS HIT AND RUN (AMAZING)/GTA V
Tycoon: Game Dev Tycoon
Racing: Need for Speed... Pro Street/Carbon
FPS: Call of Duty Black Ops 2
Platform: Sonic Heroes
Arcade: Tony Hawks Underground
Card: Yugioh GX Spirit Caller

There's probably way more but i can't think of them from the top of my head haha

FPS: CS:GO/CS 1.6
ARPG: Diablo franchise, Mount & Blade franchise, Mass Effect franchise
MMORPG: Helbreath
Open world: GTA V
Indie: The Cat Lady
Strategy: Total War: Rome II
Survival: H1Z1

FPS: Vietcong
RPG: Risen 2 (yeah... :D)
Racing: Flatout 2
RTS: Stronghold: Crusader
TPS: GUN
Adventure: Machinarium
Action Adventure: Assassin's Creed: Black Flag

FPS: Battlefield: Bad Company 2
RPG: Final Fantasy ................
Turn-based Strategy: Valkyria Chronicle

Skin Simulator: CS:GO

RTS:
Planetary anihillation
Supreme Commander
Spellforce
Grand Strategy:
Europa Universalis 4
Hearts of Iron 3\Darkest Hour
Crusader Kings 2
Sandbox:
Garry's Mod
Space engineers
Terraria\From the depths
FPS
CS:GO
Planetside 2
HL:2
RPG
TES Skyrim
Two Worlds 2
Fable the lost chapters
Oters
Beat hazard
X3:Terran Conflict
Kinetic Void

FPS: Borderlands 1 & 2
RPG/JRPG: A Lots
RTS: C&C General/Zero Hour
Indie: A Lots

RPG: Witcher 3 is fu**ing amazing! But that can be temporary... As for all times; Baldur's Gate 2
MANAGER: Transport Tycoon Deluxe
Grand Strategy: Crusader Kings 2, Knights of Honor
RTS: Age of Empires 2
Turn-Based: Civilization V
FPS: Half-Life
Racing: Richard Burns Rally
MMO: Guild Wars 2

FPS: Unreal Tournament 2004
RTS: Ground Control: Dark Consiparacy
RPG: Deus Ex
JRPG: Final Fantasy VI
ARPG: Mass Effect 3
Adventure: Still Life
TPS: Remember Me
Sandbox: GTA: San Andreas
Casual: Brink of Consciousness: Dorian Gray Syndrome
Racing: Need for Speed: Most Wanted 2 (I'm a very lowly dirty casual when it comes to racing games…)
Uncategorised: To the Moon

FPS Multiplayer: Killing Floor - Battlefield 3 - Goldeneye - CSGO
FPS Single player: Bioshock - Halo Reach
Third Person shooter: Gears of War 2 and 3
Third Person shooter stealth: Metal Gear 3 - Splinter Cell Conviction
Platforms 2d: Super Mario World - Rayman Legends/Origins - Donkey Kong Country
Platforms 3d: Mario Galaxy 2 - Crash Bandicoot 3: Warped
Survival Horror: Resident Evil 2, 4 and 5 - Silent Hill 1 and 2 - Dino Crisis 2 - Alan Wake
Run and Gun : Contra 1 and 3 - Metal Slug serie - Sunset Riders
Beat em up 2d : Cadillacs and Dinosaurs - Teenage Mutant Ninja Turtles: Turtles in Time - Final Fight
Beat em up 3d: God Hand - Batman Arkham Assylum/City/Origins
Sandbox: Grand Theft Auto Vice City/ San Andreas/ V
RPG Open World: The Elders Scroll: Skyrim
RPG Based turned: Final Fantasy X
RPG real-time combat: Dark Souls 1 and 2 - Demon Souls - Bloodborne
RPG 2D: Castlevania Circle of moon / Dawn of Sorrow
Hack and Slash : God of War 1 and 2 - Devil May Cry 3
RTS: Warcraft II - Age of Mythology - Rome Total War - Starcraft
Fighting: Tekken 5 - Street Fighter II - Dragon Ball Budokai Tenkaichi 3 - Mario Smash
Racing: Need For Speed 3 , Undergorund 1 and 2 - Top Gear
Football: Winning Eleven 8 and 10 - International Superstar Soccer Deluxe - Captain Tsubasa III :Koutei No Chousen
Adventure: The Legend of Zelda: Ocarina of time/ Skyward Sword / Wind Waker HD
Music: Bust a groove 1 and 2
Indie: The binding of Issac
MOBA: Dota 2 - League of Legends

Its hard to tell the genres apart in some games
My top2 favorites are Counter Strike Source and Guns of Icarus.
CSS is an FPS game, but i played mostly the bhop part which can be considered indie, because a small community created it.
GOI is a mix of shooting, fixing, flying and strategy. Which is also kinda indie.

MMORPG: World of warcraft
TBS: Civilization V
TPS: Grand Theft Auto: San Andreas
FPS: Far Cry 3
Racing: Test Drive Unlimited 2
Simulation: Sims 2

FPS PVP - Counter-Strike 1.5 and global operation
FPS company - Call of Duty
RPG - Diablo 2 and Arcanum
Racing - Need for Speed Underground and Pro Street.
Sport - NBA 2003 and FIFA 2007
Simulation: Sims 2
MMORPG: i love only one WoW when i was young.
Fighting: Mortal Kombat.
Strategy: red alert 2 and heroes of might and magic 3
Adventure: Voyage: Journey to the Moon.
TPS: all GTA series without IV and V part.

Adventure: The Neverhood
FPS: Call of Duty 2
RPG: Fallout
RTS: Starcraft 2
Platformer: Terraria
Online: LoL

Story focused adventure: Prince of Persia trilogy
Competitive FPS: CS:GO
Causal FPS: TF2
Platformer: Super Mario 64 and Tomb Raider 4 & 5
Sports: Virtua Tennis
Fighting: King of Fighters 97 and 98 in arcades.
Racing: NFS Most Wanted for gameplay and NFS: Underground 2 for graphics and music.
RTS: Age of Empires 3
Turn Based Strategy: Age of Wonders 2 & 3
RPG: Fable: The Lost Chapters
Open world RPG: The Witcher 3

Multiplayer FPS: Counter-Strike: Source
RTS: Starcraft
MMO: Guild Wars
Adventure: The Longest Journey/Dreamfall
RPG: Baldur's Gate 2
Horror: Doom 3
CCG: Tyrant

FPS: Far Cry
RPG: Gothic 2 + Night of the Raven addon
Sport: Fifa 14
RTS: Warcraft 3 + Frozen Throne addon
Multiplayer: CS:GO
Adventure: Syberia
Racing: Need for Speed: Most Wanted (2004)
TPS: GTA series