What's your highest playtime in a game?

Almost 200 hs on Terraria.

I have about 2700 hours on 4th generation Pokemon games (Diamond, Pearl, Platinum, Heart Gold and Soul Silver) due to playing competitively for a long time. Other than that? I've beaten Chrono Trigger around 70 times at 12 - 13 hours each, Final Fantasy X I had 218 hours on my file when I stopped playing (And still hadn't unlocked everything yet)

I think around 500 hours on Pokemon Pearl.
Defeat Elite Four. Repeat.
Defeat Elite Four. Repeat.
Defeat Elite Four. Repeat.

Terraria - 134 Hours.

Game time as steam takes it in? Then TF2 gets it. But real playtime is being battled out between CS:S and Dota, but dota seems to be winning slightly.

StarCraft II - 500+ hrs.

Real playtime: Dungeon defenders (168 hours)

Probably around 11000-12000 hours in WoW (used to be really hardcore...)

As for Steam games, 330h in CSS.