Best game fanbase?

Dawn of War
That mods... that awesome mods made by awesome people

What about Minecraft?I remember it had a extremely active and big community, but I don't know how it is doing right now...

Lego Rock Raiders.

I'm quite serious.

not dota2

Back in the day: Unreal Tournament

Now: Killing Floor

Future: PLEASE MAKE ANOTHER GOOD UNREAL!

:-P

Guardians of Middleearth. tons of players, running perfectly, noone is disconnecting and the players are soo friendly....Joke aside, the best fans are the (hot) cosplayer girls ;) and you can often see League of Legends cosplayers, so that would be it, even though the players can be idiots (still better than Dota, even though I prefer it to LoL)

San andreas multiplayer (Its a third party mod.)

Garry's Mod, Team Fortress 2, Dota, Minecraft

probably these games will sustain a lot of players

World of Tanks, Lol, Dota2, Minecraft.... ok enough with the jokes, i personally like the Terraria community alot!

what content? :) amazing chests and jumping off? :)

I'd say Touhou

I'd have to say Killing Floor. It's been out for 4 years and new updates, content, maps, etc . . . are constantly produced. The development team is awesome, and same for the player base.

Starcraft 2, okay, i got flamed a few time for playing protoss but most of the Guys i met were pretty cool and helped me out a lot as a noob. There are cool barcrafts around the whole world and homestory cup is badass!

S.T.A.L.K.E.R. Shadow of Chernobyl. 6 years later people still works on mods which several times bigger than original game

Praise the sun.
I don't play much multiplayer anymore, so I wouldn't know

All the 5 Blizzard games i ever played do have good community´s.

StarCraft II Wings of Liberty i never met a jerk.
Diablo 3 most players is friendly while some can be a jerk sometime.
Diablo 2. We all know it, the best game in the world, forever. Not many players left but stil a good community and very fun game. However get Lord of Destruction else there are 0 players
Warcraft 3. I dont think there are many players you will need Frozen Throne then there is enough players. You can make maps to change the gamemode itself. Dota was also made as a WC3 map.
World of Warcraft. Fun game if you have friends playing it. Alone it will be boring. One of the best community i ever been apart of.

Bad communitys:

Dota 2, LoL, HoN

Two years? That's not really much. In terms of mods, there are still many being user made (and being supported/used by other users) for Oblivion, Skyrim, GTA IV, Civilization IV, Civilization V (looks like it can go for another 6-12 months seeing that even the developers are still dishing out content aside from the user mods), Minecraft, SIM City 2000 (not sure about this one).

Another thing to consider are MMOs -- a quick google search of "Longest running MMO" should do the trick. These ones also lasted pretty long -- Starcraft:Brood War, Warcraft III+Expansions, Counter Strike.

Anyway, unique game titles running for 2 years with a strong fanbase is getting more uncommon because MOST popular games get a sequel the next year.

I'm a fan of Dota 2 but I think the fanbase is larger in LoL

Quake

Call of Duty and Battlefield (>2) or course trolololo

skyrim!

Morrowind...If you don't know what that is leave now and forget you read this, you don't deserve to know it's name.

The Elder Scrolls Series!

CoD4 Modern Warfare 1, has more people playing than every non-current cod combined (so basically everything except ghosts). Not to mention how old the game is now, people are really cool for the most part.

the sims 3