I'm a real fool for any scenery that has snow in it;
Final Fantasy 6: The intro credits scene! Also, the whole place surrounding Narshe.
Final Fantasy 13: The frozen place right after the pulse vestige battle.
TES3-Morrowind; Bloodmoon expansion: Solstheim. Glorious!
TES4-Oblivion: The northernmost province of Cyrodiil on highest graphical settings.
Minecraft: maps with the right texture packs (but, that's what I've seen from gameplay as I've not played it myself)
That's an excellent question. Some environments are really well made. A few that come to mind firstly are Red Dead Redemption and oblivion. Mainly because the colors are so vivid and lifelike and every inch of land seems like it's something special. However, I can also see Rapture from bioshock included in the mix. Mainly because they were trying to set the environment as something special. Being both underwater and in the sixties. THey pulled that off excellently and, in turn, set up an entire world for you.
I'd like to say Twilight Princess's Hyrule. For some reason, I really liked the aesthetics, it was brown and bloom done RIGHT, and really complemented the style of the game itself. Plus, Sunrise in that huge Hyrule Field, while riding Epona was amazing.