I loved the environments of FFX, everything seemed to have so much detail, from the ambient lighting in the Thunder Plains to the slight eerieness of the temples, especially Macalania temple.

The only fault I could see with X in terms of environment is two things, first, Spira is incredibly linear, it's essentially a South to North Pilgrimage. Also, most areas are quite badly transitioned. You have the Moonflow and Guadosalam, which is full of woodland, then the desolate thunder plains, followed by the icy Macalania, then out towards the temperate Calm Lands.