Planetside 2 for god knows how many (client based, not on Steam)
Starbound - 85hrs.
Dying Light - 59hrs
GTA V - 42hrs
Planetary Annihilation - 29hrs
Minecraft - insane amount of time since 2011
Titanfall - Probably over 100hrs
WoW - played since 2004 so I'd imagine the MMO is my most played game of all time.
FOr an SP game, Starbound I'd say took the most time while WoW/Titanfall took up my MMO/PVP time.
Step right up come on in, feel the buzz in your veins, I'm like an chemical electrical right into your brain and I'm the one who killed the Radio, soon you'll all see
So pay up motherfuckers you belong to "V"