World of Warcraft. Over a year of game time. I'll get an exact number and post It. that's only 2 characters too.

222 days 4h on my current main (vanilla/bc/draenor)

111 days 14h on my old main (bc/wotlk/cata)

33 days on all my other characters combined.

I didn't plays at all iN Panda Land.

No way for me to know how many hours i played total in melee and brawl, but i know

Warhawk on ps3 is 350+ hrs

Dark Age of Camelot. I remember hitting max level with my first character in 36 days of play time (865ish hours). That was in the first 6 months of playing. Played for another 5 years. Gotta be around 6000-7000 hours or so all told.

Edit: so I did the math, and it was probably closer to 11,000 hours.

Three way tie between
Dragon Age Origins
Skyrim
Fallout New Vegas

Dark Souls - 250h+

I spent a tragic amount of time playing Final Fantasy XII, around three hundred hours I believe, but then again, I did have a weird habit of leaving the console on while I slept.

Age of Empires II for untracked amount of time.... probably around 1000+ hours?

one year???/

1. Runescape (across 3 main characters spanning 10 years, still play it from time to time)
2. MapleStory (across many characters but played on my main for over 6 years)
3. League of legends (142 days wasted according to wastedonlol.com, played since february 2010, currently platinum III)

CoD4, around 80 hours, took about 3 years to reach that.