>>31322166I've always really liked Old Chateau. Definitely the best haunted area imo. It's one of the only places in the older games that I can believe "Yeah, somebody lives/lived here at some point." I dunno why, but the dining room in particular feels so good and satisfying to me. And being a completely optional area helps.
Rotom's cool too, and the ghost npc here is probably my favorite of them.
Also DPPt's soundfont is really good at that creepy feel.
https://www.youtube.com/watch?v=6VtewUF9yJU