Quality aside, for me, the #1 game would also be one that I could reasonably play for the rest of my life and nothing else.
So, does the choice include any and all possible mods for such a game? If yes, then Fallout New Vegas.
Anyway, I'm tipsy and it's too humid outside to meet my future wives, so I feel like kind of elaborating why this, and not other games.
Is the GameBryo incarnation of it shit? Well, it is, and is not, at the same time. Definitely, the graphics are the lowest possible point there, but those Bethesda kind of games do some things, that other games will not or cannot replicate easily for this reason or another.
But I simply have to concede that there are parts of it that are stellar, even (or especially) by today's standards. Even aside from obvious strengths of it, regardless of the game itself like writing, dialogues etc. that would be great regardless of the form they're given in, there are parts of it, like level design or art direction, that just recreate that Fallout 1/2 feeling perfectly, or as perfectly as is possible given the switch from bird's eye view to 1st/3rd person. It's something I noticed with Freeside Open for the first time, but walking around Freeside/Westside/North Vegas and those "empty" huge rectangular buildings is a 1:1 recreation of walking around shit like The Hub or New Reno in OG Fallouts.
Also, given that this game is in one way or another a shooter, I have never, ever seen such gun porn in my life. If not for FNV I would not even ever think of such a term. I was always flabbergasted why Bethesda never thought of it and their games just go with some makeshift jury-rigged peashooters*, as the selection is just ENDLESS. To give just one example, I think Riot Shotgun gives is on Doom 2 SSG's level of impressiveness. I could give as many such examples as most of the weapons in-game, and on an RPG side it makes even stuff like Explosive builds 110% viable. And the majority of this stuff would just not work as well, if not for sound design, which is just perfect all-around.
Pertinent to the last point, playing this game with the Bloody Mess perk, even vanilla, is something that makes Brutal Doom pee its pants on all fronts, and didn't the latter come out later lmao. It's gibs everywhere, it's gibs, eyeballs, brains, plasma-melted corpses or piles of ash. I always chuckled when it came to looting all those "bodies" and looking around which part of the leg or eyeball belonged to whom. That kind of shit just isn't the same with Fallout 4 Creation and it's wimpy and flaccid design.
Lastly and obviously, as mentioned already on a daily basis, it's modding that is the strongest part of those games, but I'll let the last part speak for itself as I'm sadly sobering up.
1* I will give credit where credit is due and say that Fallout 76 post-Wastelanders, is simply far superior to F3/4 in this aspect as well. It took inspiration from New Vegas/Tactics by bringing back cool stuff like Winchester P94, Grenade Machinegun, or even simple things like SAA Peacemaker, to flatout crazy shit like explosive Gauss Minigun.
