SAngband. I never really finish any of the longer roguelike games, but it’s fun to take a character or two to the depths of the dungeon like every two years. You could go as far as to claim it is one of the latest versions of Moria, which would make it almost 30 years old by now. I’ve only been playing for 22-23 years, though.
Baldur’s Gate 2. The player-made mods make it awesome and very replayable.
I guess I would go with Alpha Centauri, although I have not played it recently. Or maybe Heroes of Might & Magic 4, although I might get tired of the campaigns eventually.
Pong?
Tropico III
Galaga.
Speedball 2: Brutal Deluxe
General Chaos
I end up going back to Master of Magic every few years. With other games there’s usually been something better to come along eventually. For example Civilization II was replaced with Civilization IV for me, but I’m still waiting for a fantasy strategy game that could surpass Master of Magic.
If it was just one video game I was stuck with for the rest of my life, I’d have to go with something like Starcraft 2… but that’s kind of cheating because it includes a rich online community with amazing custom games that just continually add content and keep changing. Starcraft 2 is kind of like 1000 different games in one, and the new games just constantly keep changing, getting better, etc.
Now, I know the OP said we should just limit it to one game, but if we have to limit it to a static game that isn’t constantly changing, getting updated, new custom content and mods and whatnot… then I’ll have to go with Star Control II: The Ur-Quan Masters. It is just such an amazingly fun game to play, I doubt I could ever get tired of it. I go back year after year, and the jokes, the dialogue, the characters… all so fecking amazing. I just love it. Plus it has a great skirmish mode you can play against other humans or CPUs which is a blast.
Chrono Trigger (very close to ffvii). I find myself downloading it and doing 2 or 3 playthroughs every other year… I can’t help myself.
I could play Civilization pretty much forever.
Tetris
For stand-up arcade games I could play Robotron: 2084 for the rest of my life.
Chrono Trigger is definitely one of them. I’ve got it for the SNES and for the Playstation. FFVI/VIII are also contenders.
Half Life
Half Life 2
Football Manager
Europa Universalis III.
The Worms franchise, specifically the 2-D iterations, Most recently Worms Reloaded.
GALAGA - simply the best game ever for video-tards like myself.
The best thing is I got a PS2 way back for a present and the only game I play with any regularity is GALAGA, part of the NAMCO 20 year anthology disk.
I truly suck at video games. Uber suck.
Either Assassin’s Creed Brotherhood or Minecraft.
I’m on my third replay of ACB and I’m still finding new stuff in it. I don’t know what black magic those wizards at Ubisoft Montreal used to produce that game in only a year, but as long as they keep making quality Assassin’s Creed games like that, I will be one of the first in line to pre-order.
Minecraft is the epitome of a sandbox game. By itself without any modification, the sky’s literally the limit. But if I can mod it, it will be impossible for the game to get old, especially since I’m capable of writing mods myself.
Between the two, I’d have to say Minecraft since there’s no limit on creation of new content.