Oh man, I wish I had more spare time for games.. For me it's
Witcher 3 - 121 hours (5 days)
Skyrim - 99 hours (4 days)
Dragon Age: Origins - 90 hours (4 days?)
It may not surprise you to know that Fallout, Borderlands, Deus Ex, Borderlands, and BioShock are not far down. I do like my Campaign-based RPGs :)