TF2, L4D, Skyrim and C&C Red Alert 3 are probably the few I've spend more than 200 hrs on.

Dark Souls. ~150 hours on Steam, and I plan on playing it over and over for the rest of my life. A masterpiece.

At worst, World of Warcraft... i've been playing for 4 years until Cataclysm released. Started from August 2006 to December 2010. Bethesda crushed my addiction with this announcement trailer. xD

https://www.youtube.com/watch?v=dWUS0-0tn4g

After this.. I started playing Fallout New Vegas about year later.

I've had 9 or 10 Pokemon Ruby save files where I maxed out the clock at 999:59, so probably that.

Battlefield 4 1500 hours and still going.

WoW 400+ days
LoL 70 days
FFX and FFVIII 20 days
Koei games 30-70 days?
Age of Mythology, Medieval Total War, Rome Total War, Civ 3, Crusader kings 2, Stronghold crusader, C&C games 100 hours each.

Definitely cutback recently, but games can easily be replaced by tv shows, books, youtube videos, etc.
For example I have watched over 150 hours of One piece and Bleach.

Animal Crossing on Gamecube. I've been playing it daily since 2002 so, I'm pretty sure my hours played beats any and all of the people's in this thread lol

Fire Emblem Radiant Dawn.
Easily done over 900 hours.

However, for current gen, it's Splatoon with like 133 hours. This month it's Xenoblade X with about 75 hours.

Destiny = +425 hours

Warhammer Online, at least 1 year of playtime (I'm afraid to think two) since 2008; current emu counts, too.