Halo 4 easily. 343i really... And I mean really, leveraged it's artists extremely well. - Strip back the artistic assets and graphically Halo 4 would be pretty average... I.E. Allot of models are extremely low polygon, but you wouldn't pick it at first glance.
The subsurface scattering on models faces were pretty jaw-dropping back in the day too.
--::{PC Gaming Master Race}::--