1) Disgaea: Hour of Darkness
2a) Final Fantasy VI (if you count the number of times I've gone through the game)
2b) Morrowind (if 2a did not count)
3)Skyrim

TIE Fighter: Collector's Edition
TES: Morrowind
TES: Oblivion

Nothing else even comes close.

1 - Minecraft (I don't even want to know how many hours I've lost to Minecraft)
2 - Skyrim
3 - Lord of the Rings Online

1) Pokemon
2) Knights of the Old Republic
3) Sengoku Rance

1. Minecraft

2. Skyrim - been playing since release and still haven't picked a side to fight for. Though I am Thane of almost everywhere.

3. Disgaea Hour of Darkness - You know you will play a game for a long time when each item has 100 levels inside of it, and you can reset your character levels to gain huge stat bonuses.

In no particular order:

Call of Duty (the first AND best of the series).
Medal of Honour: Allied Assault (+ Extentions Breakthrough and Spearhead).
World of Warcraft

The Night Angel:
1- Oblivion
2- Final Fantasy X
3- Final Fantasy 12 (what?? I actually kind of liked it :P )

FF12 is a great game people only hate on it cuz it deviated from the formula =p
I for one love 12, it was far better than the snooze-fest 13 was.

OT:
1- Battlefield Bad Company 2 stole well over 500 hours of my life.
2- Pokemon Gold.
3- Final Fantasy 12.

1.Counter-strike - heh still ejoying a match or two.
2.WoW- well you know, it's WoW
3.Starcraft - regular player since 1998.There hasn't been a day in my life i havent's spend zerg rushing.

Among games that actually track hours... the only one I've gone over 100 in is Fallout: New Vegas, at 558 hours currently.

But I've definitely played City of Heroes more than that, considering I played from 2004 to 2008 and still play sporadically (though I can no longer access all of my 60+ toons >.< )

So it's

1-City of Heroes/Villains
2-Fallout: New Vegas
3- ...err... probably Chrono Trigger, considering how many times and on how many different platforms I've gotten all of the endings. Then again, in Final Fantasy Tactics(War of the Lions) I've maxed a few characters out before... I've also put a whole lot of time into Gran Turismo 5, though I'm not certain if it compares...
I suppose number three is unknowable.

1) Fallout 3. Over a thousand times saved, several playthroughs, most of them 100+ hours.

2) Fallout New Vegas. I like Fallout, have you noticed?

3) Spyro 2: Ripto's Rage. Hey, this game was my childhood.

TES: IV Oblivion around 700+
WoW... I don't even want to know...

Then either FO:3 300+ or DA:O 300+, not sure.

Damn now i have to admit im still stuck in the last gen of games lol.
1. Morrowind(still play it even)
2. Kotor(dust it off now and again for a play though, even better on the 360 cause i got the Yavin download for free.)
3. Champions of Norrath.(me and a buddy were unemployed at the same time and maxed out quite a few characters in this one.)

1. D2
2. D2: LOD
3. WoW(Release till mid Cata)

1. Fallout 2
2. Arcanum: Of Steamworks and Magick Obscura
3. Victoria 2

1. World of Warcraft (500 days, give or take)
2. Warcraft 3 (100-150 days, not sure)
3. Call of Duty 4 (49 days)

Honorable Mention: Halo 2, Pokemon Red/Blue/Yellow

1) World of Warcraft
2) Morrowind
3) Black & White 2

I usually really hate playing games on a PC, so I find it kind of odd that my three most played games are all on PC. Huh.

1. Warcraft III
2. Fallout III
3. Dragon Age Origins

Ive played 4 games about the same amount of time
fallout 3
fallout new vegas
skyrim
and xenoblade

1)TES IV: Oblivion-300+ hours(could be MUCH higher)
2)Football Manager 2012-250+ hours
3)TES V:Skyrim-Time not available at the moment.

1. Europa Universalis 3 - Divine Wind
2. Fallout New Vegas
3. Victoria 2 - A house divided

Hard to tell, most of the game I played don't keep track or are almost a decade old but I'll guess and then add some actual numbers from my Steam account

1. Runescape (Free way to get the MMO grindy experience)
2. Medal of Honor Allied Assault (Bolt action rifles only, 1 hit kills, round based objective)
3. Battlefield 2 (Strike at Karkand Infantry only 64 Player conquest)

As for games on my Steam account with actual numbers behind them

1. Team Fortress 2 (Before they ruined it)
2. Counter-Strike, as a series probably more than 500 hours
3. Fallout: New Vegas

Counter-strike is actually probably my most played series but Steam didn't keep track of hours played when it came out and was therefore the only game I played for about 2.5 years.

And I have over 300 hours on Advanced Wars: Dual Strike on the DS

1) Team Fortress 2 - Many many hours pumped into this game. I think I've gotten pretty good at it too

2) Street Fighter 4/Super Street Fighter 4 - Also spent a lot of time in this, probably close to TF2 in terms of time. Still consider myself to be pretty bad at it.

3) Call of Duty: Modern Warfare 2 - I enjoyed this game quite a bit, although it made me quite angry at times. Not played nearly as much as SSF4 and TF2, but still a fair bit.

1. Civilization 4
2. Champions Online
3. Not sure but it's one of Civ 2 / Alpha Centauri / Civ 3

Morrowind well over 300 hours, after I had literally done everything I preceded to kill every NPC in the entire game, all that's left are really mad guards that respawn.

Fallout 3, over 240 hours. I've replayed it more than a few times using different builds.

MineSweeper, over 20 years... nuff said

1.Oblivion
2.Oblivion: The Shivering Isles
3.Fable: The Lost Chapters
In regards to the first two I'm still trying to overtake the hours of my life I've spent on Oblivion with non-oblivion hours, I've got a long way to go

1.World of Warcraft

2.Gothic 2

3.Diablo 2

Civilization III,
Civilization II,
ISS Pro Evolution.

1) Pokemon Yellow
2) Mass Effect 2
3) Dragon Age:Origins

Although, thanks to the incompetence of EA, Casey Hudson and Mac Walters I will never pick up another Mass Effect game again, so that will soon be replaced by Skyrim.

Multiplayer/MMO's
1) WoW

Single Player Games:
1) ME1
2) FO3
3) Skyrim (slowly climbing still)

>>damn double post<<

Easily my number one:
Saints Row 2
The number two and three spots I cant be sure about, but they are either Oblivion, Fallout 3, or Saints Row the Third.
If you count multiple games in the same series though, Pokemon is number one by weeks worth of gameplay.