I've been playing since the NES and despite being from a low income family I had the luck of being able to play and own many consoles over the 3 decades of my life, plus some pc.
If you ask me right now? Resident Evil 4 (2005).
A before and after in gaming, to this day still extremely fun to play even for casuals but 20 years ago it was THE masterpiece. And everyone took notice of it, everyone played it, even players that didn't cared about resident evil. The gameplay was so good that it got photocopied by everyone right after in the action genre.
Arguably the last big innovator in videogames minus Minecraft and... PUBG (Fortnite did it better I know).
Try to NOT pick your favourite game, that's a different thing.
Never understood people's obsession with RE4. It completely changed the series from survival horror to action shooter, as if we didn't have enough of those already. One zombie used to be terrifying. Now there's hundreds coming at you at once and they go down easily. They removed most of the puzzles too and dumbed down the ones they left. Somebody please tell me why everyone loves this game!?
Give me the first two Resident Evils over the 4th one any day. Hell, I rather play RE3 than RE4.
What's more relevant to the world? What felt like an evolution? I love almost every RE but 4 did history for the entire gaming universe, not just horror.