You can only play ONE genre forever, which is it.

[Veylon]

Whatever the heck genre Dwarf Fortress and Minecraft are in.

 

[Bender Rodriguez]

Plattformer/Adventure.

 

[York_Beckett]

RPGs are always good to count on.
Not JRPGs though; that would essentially be like playing the same game over and over again.

 

[Frotality]

RPGS...but ones that take after their table-top precursors with diverse classes, abilities galore, and countless ways to customize you characters. not the shooter/hack'n'slash where you level up that RPGS seem to be becoming.

 

[Blitzwarp]

FPS, definitely. I never get bored with shooting stuff. XD

 

[Socius]

Roleplaying games!
They last longer and are more fun in general, even if there are fewer of them than First person shooters or action adventure games it's the content that makes them what they are, not their quantity.

 

[littlealicewhite]

RPGs, no doubt.

 

[Redlin5_v1legacy]

I'm unsure... Just what genre is Freelancer anyway

Probably RPG though.

 

[bassdrum]

I'd go with RPGs, because that's a label which encompasses a pretty huge variety of games. By only playing RPGs, I would still be playing a lot of the games I love (i.e. Fallout, Bioshock (if you're willing to accept it as an RPG), and Mass Effect), some of which are also reasonably good shooters (i.e. Fallout, Bioshock, and Mass Effect). It would suck to be forced to leave so many games behind--the inability to ever play games like Red Dead Redemption or Minecraft again would probably make me rather sad, but at least I'd have a large selection of awesome and varied games at my disposal.

 

[Steampunk Viking]

Easy question, anything classified as an RPG. For me, it's all about games like Mass Effect, Dragon Age, Knights of the Old Republic, Baldur's Gate, Final Fantasy (the older ones at least), Fallout (it's technically an RPG/Shooter, HYBRIDS COUNT!), Elder Scrolls, Lost Odyssey... the list goes on and on. They take longer to complete, have a much more indepth story, more customisation (I love my customisation) and are generally just more awesome.

Also, MMORPGs are also RPGs, so I wouldn't miss out on WoW or The Old Republic either

 

[Polaris19]

RPG.

Sheer number of countless experiences and the amount of time each can be enjoyed far outlasts any shooter or sports game I own.

 

[havass]

Sandbox. I love sandbox games and they're sprawling enough to entertain me for the rest of my life. I could play games like Just Cause 2, GTA and Assassin's Creed forever, no problem.

 

[SMILEYkyle21]

The skate games, as long as they kept updating the maps i would never get bored of it. the only thing more satisfying is actually skating lol

 

[SmokingMirrors]

Roleplaying Games. No competition there.

 

[infohippie]

Just to be different to everyone else, I'll have to go with RPGs.

 

[Cyberjester]

Minecraft. Sure its a game and not a genre but with time.. With time, it will have RTS/Adventure/Rpg/Build-- You name it. And even without all that it can still entertain me for forever.

Sandbox.
It's applied to GTA as well, so you're in luck.

europa universalis iii or smac

Th.. Wait, what's smac?

EU III though. Real Time Strat.. No, Strategy. I choose strategy. Since I'm not sure whether EU III, Napoleon Total War, Company of Heroes and Dawn of War all go into Real Time Strategy since they're fairly different games. Similar, but different.

So yea, strategy. I like world domination, I like taking on armies of 500 with 300 and winning through tactics and general intelligence. I like the challenge that comes from the equivalent of high speed chess against 7 other players at once. It's an intellectual challenge that I adore and would give up my FPS for. In this unholy universe where I can't play Deus Ex Human Revolution. :'(

 

[Sethzard]

Sandbox RPGs I guess e.g. oblivion and morrowind

 

[wammnebu]

europa universalis iii or smac

Th.. Wait, what's smac?

EU III though. Real Time Strat.. No, Strategy. I choose strategy. Since I'm not sure whether EU III, Napoleon Total War, Company of Heroes and Dawn of War all go into Real Time Strategy since they're fairly different games. Similar, but different.

Sid Meier's Alpha Centauri, if you like civ you might want to check it out

I think EU III and the Total War series are called "grand strategy" or something since they combine both real time and turn based. Don't quote me on that though.

I figured since i already have 114 hours into Civ V since it was released and 24 since i got EU3 last week, i could play them forever and not realize it.