Arma 2, all maxed out (200% resolution, 8xAA, FXAA, 16AF, 10k view distance, all very high), can be quite the looker, especially from the air.
A modded Stalker, also looks great, Just Cause 2 it's nice, Metro but without the DoF which can blur some textures, Il 2 CoD, Crysis and Warhead, MP 3, TW 2, Skyrim/Oblivion/Morrowind with modds and so on.
Most of those games give "something beautiful" through their graphics, from some, a melancholic feeling of some sort - Stalker, Arma2, perhaps Witcher 2 combined with it's very good story line and characters.
Truly next gen games we will see soon I hope. Watch Dogs should be one of them, Good Samaritan should also give an approximation on what games will look in the future.
PS> Arma 3 is definitely a game to keep an eye for. PC only with great lighting system and graphics -
https://www.youtube.com/watch?v=mIwfS8uJJIk