I'm no MMO fan, so for me the most time-consuming was Daggerfall. But then, I really ike this game.

On the off-topic side: is it just me, or did the 'post the random fact...' topic somehow got deleted?

*facepalm*

And more on topic 4 words "Just one more turn...."

I quit at the end of TBC with over 200 days played on my main and 100 on my favorite alt. I had a level 59 twink pvper with an epic mount (yes, I got rank 11 under the old pvp system with a level 59 character) 3/5 Zul Gurub gear, and I can't even remember what else. He was lock and I used to taunt rogues by /sit in the middle of battlefield, they could never resist and they always died. I also used him to hunt down and kill level 60 High Warlord warriors in world pvp.

Yeah I spent way too much time on that game.

If we are talking about single playthroughs, then some RPGs reach 100+ hours, as long as you go for sidemissions etc.
Longer than that (always for single games, not starting new) you would have to look for either open ended strategy/sims or MMO games.

For example.
The game Colonial Conquest by SSI (old game), a single game could take more than 100 hours, especially if you played on harder difficulty and/or with some additional human players.
Some of the Evochron games can reach more than 100 hours as can the X series.
Personal record for single game I would say a large winSPMBT PBEM campaign, with each battle needing between a week and a month on average to finish (few hours each day), which means the campaign/war getting to half a year or a year to finish.

Empire Deluxe can also take many many hours for a single battle, at least on large maps.

Carrier Command, if you play a strategic game and don't a shortcut, it can take several days, if you use time compression, else weeks.

And of course the absolutely monster Elite Frontier where if you don't use Warp, you might as well just write your will for your grandchildren to write their will etc for several generations till your ship reaches just one of the out of the system planets.
:p

I used to use the timewarp bug for instant landings it saved alot of hassle

For me Arcanum. As I started it I hoped to beat it during my University summer vacation (4 months) - but I didn't make it. Then it had to wait for next year...All in all 6 months of everyday playing. But of course I'm not hardcore player - I have a job so I couldn't play as long as I wanted.

Every month you wait will make it harder.

Blizzard games in general, all of them just have so much replay value and lifespan

Well....that and the elderscrolls games

Any game where you can reload a save and kill a monster again for a different loot can have me spending huge amounts of hours in exactly the same moment in the game. Pretty LOL on my part, but something about doing that has a weird appeal.

Huh, well if we're talking about a sandbox-y, free play type game, I'd say the Civilization series + Alpha Centauri.

If we're talking about games that just have a loooong period of time in a single playthrough, Dragon Quest 7 was ridiculously long.

for me it would be football manager (previously championship).. there's simply no end to that game :)

i know that playing war in the pacific through takes around a year of an average gamer's lifetime.. i'm yet to verify this myself :)

Tetris. I must have spent half my childhood playing this game.

Civ IV... Just developing play styles for each civilization and leader takes forever, but it's still fun every time.

From commercial games, I'd say Killing Floor has accumulated most game hours at the moment.

But recently I found another game that has been eating away my free time a lot. This game is VERY addictive. The game is called...

Minecraft.

I expect to catch up with Killing Floor game hours in a few weeks... <.<