The kitchen in Irithyll (DkS3) because of its contrast to the surroundings - warm and orange compared to the cold, wintry blue outside. Perfect place for a respite between a couple of grueling gauntlets. Also super cozy. Also a reminder to go save Onion Bro if you haven't. Also, a toast!

The summit of Sorrow Pass in OatBF also because of its contrast to the surroundings. After hours of trekking through darkness or mostly-darkness, it's the only place in the game where you get to see the sun. It's hard to leave.

Besaid in FFX. I'd live there.

The Crystal World in FFIX. The monstrous enemies, the ethereal "landscape" for lack of a better term. It's memorable because the game conveys to the player that "you do not belong here." The music also reinforces this. If there was ever a place in fiction that gave you the idea of being at the end of the physical universe, this place nailed it.