1 - racing simulators - Gran Turismo
2 - Action Adventure - Uncharted
3 - Final Fantasy (a mix of story heavy, great graphics, for me it started in this, but JRPG itself isn't one of my favorite genres) - FF IX.

Nintendo / PlayStation

1. RPGs (mainly with japanese sensibilities)

2. Action-Adventure (but not stealth or horror ones)

3. Platformers

I like this topic, although I feel like genre alone doesn't speak adequately to the different fan bases. You could group Breath of the Wild, Sea of Thieves, and Uncharted 4 under action-adventure, but all three play very differently due to the mechanics and designs underpinning them.

Back on-topic...my favorite genre is action, with a special focus on action-adventure. Basically anything where there is a balanced mixture of real-time action, puzzle-solving, and exploration. A few games that typically fall under "shooter" could in theory be labeled action-adventure, like Half-Life 2 and BioShock. Some of my favorite series under this banner include The Legend of Zelda, Metroid, and Resident Evil.

Another subset of action I love is platformer, which at times overlaps with action-adventure. Series like Metroid, Castlevania, Ori, and Guacamelee arguably belong under action-adventure, but they certainly focus on platforming to some degree. Even 3D platforming games like Banjo-Kazooie, Psychonauts, and Super Mario Odyssey -- all favorites of mine -- share something in common with action-adventure. My favorite platformer franchises include Super Mario, Donkey Kong, and Rayman.

A third favorite: role-playing game. This includes "classic" turn-based affairs based on the pen-and-paper variety and their cousins in the action-RPG camp, which also have a lot in common with action-adventure. I enjoy assembling a party, managing classes, upgrading characters, going on quests, exploration, etc. While I certainly gravitate toward the instant gratification of real-time action (see above) I also enjoy the tactical, methodical process of planning and executing a winning strategy in a turn-based environment. Among my favorite RPG brands: Final Fantasy, Xenoblade, The Elder Scrolls, and Souls.

I took a look at my top 20 games from mZuzek's Annual Greatest Games thread and found that 16/20 games are either action-adventure, platformer, or RPG, or some combination of the three.

My favorite game-maker is Nintendo.

1. Adventure (ex.: The Legend of Zelda, MediEvil)
2. Simulation management (ex.: RollerCoaster Tycoon, SimCity, Anno)
3. Third Person Action (ex.: Uncharted, Jedi Knight)

Obviously though there’s a lot of overlap between genre 1 and genre 3. If you’d count 3 as 1, then I guess my third favorite genre would be 3D platformers, though that’s really just one series these days; 3D Mario. After that would I guess come turn-based strategy, again just one series; Total War. In the past I liked first person shooters a lot, but nowadays I barely play them anymore, after they all got CoDified after Modern Warfare, of which I didn’t like the direction contrary to the first two games, became big. Other genres are very hit or miss to me like RPGs, 2D platformers and fighting games. Genres I don’t care about at all are racing (except Mario Kart for some reason) and sports.

My all time favorites are from all over the place, though the biggest thing remains the Zelda series. That one’s also where my loyalty to Nintendo comes from; I always buy the Nintendo console, because those get Zelda. Throughout the generations it has always been a Nintendo+ situation for me though, because there’s always been at least one other system that has enough that interests me to get it. Usually this has been the PlayStation. The PC has been the common thread however, since I’m into simulation games, I’ve played a lot on PC over the years. In fact, I’ve played more on PC than on every other system combined. Probably even twice over.

Member of the Nintendo Defense Force.

1. Platformers

2. RPGs

3. SNK Fighting games.

PC and Switch

Turn-based strategy/4X/Grand Strategy (Total War series, Stellaris, Galactic Civilizations...)
RPGs with turn-based combat systems (Mostly JRPGs and old western RPG)
Town Builders (Settlers, Banished, Aven Colony...)

Least interested in:

Action-Adventures
Military Shooters
Racing simulations

Which sadly very often feels like being all of the games on Playstation or Xbox that ain't RPGs or sports titles.

Honorary member of the Nintendo Defense Force 

I'll butcher the genres, since they're already so broad in other posts, by making them specific to the point of lunacy. So, in no order:

Atmospheric First Person Shooters

Character Action Games 

AAA Metroidvanias (Metroid Prime, REmake, Dark Souls) 

PlayStation fan. Haven't had a chance to play anything but PS for the past 20 years cuz I don't care for anything else.

My top 3:
1. Action/Adventure
2. Stealth
3. Shooters (FPS/TPS) (except Call of Duty and Battlefield)

1 : Strategy : like Crusaders kings 2 or Europa universalis
2 : Strategy : like civilization or Xcom
3 : RPG : Western & Japan.

I Would say Action/Adventure like uncharted is my top 3 if you combine the strategy under one choice.

Nintendo fan.

1. Western RPG
2. Platformers (don't make me chose between 3d and 2d.
3. Action Adventure, with an emphasis on the adventure.