I haven't gamed that much at all in the last decade, so the pool I have to choose from is small, but....
PC : Battlefield 3
This is the last game I played on PC, so an easy choice. Battlefield 2 is my favourite game of all time and coincided beautifully with those lazy teenage years spent playing with mates. Bad Company 2 was great, but didn't feel like a proper follow up. Battlefield 3 had everything and was great fun. I'll be building a new PC in the coming weeks and plan on getting Battlefield 4 and possibly 5, so it will be interesting to see how they stack up.
Console: RDR2
Not only does this game looking stunning, even on a regular PS4 @ 1080p, but the open world was great as well. I've played it through twice now; the first time mainly story focused and the second time doing all the side stuff and challenges. Absolute masterpiece as far as I'm concerned.