I'm not just talking about Snowhead Temple, here, but the entirety of the Snowhead region in Termina. If I were only talking about temples, I probably would have picked Snowpeak Ruins from Twilight Princess or the Ice Palace from A Link Between Worlds, but I'm not.
Snowhead was one of the most memorable locations for me in Majora's Mask as a whole. The Goron people, here, are literally freezing, some of them to death. After finding the Lens of Truth, Link discovers the ghost of a Goron, and he plays the song of healing to help them move on to the afterlife.
The entire town is in ruins and despair. It has been cursed by the evil spirits up in the Temple. Not only this, but the moon looks to be getting closer with each passing day. The feeling of dread that hangs over the air in this winter town is unmistakable.
After beating the boss of Snowhead Temple, the land surrounding the base turns green again, and the frost thaws away. The Goron people defrost and marvel at the sudden change in weather.
"It's a miracle! We've been saved!"
The Snowhead region is unlike any other region in Majora's Mask in that it completely comes back to life after beating the boss of Snowhead Temple. The scenery completely changes.
Some people may argue that Ikana has the same effect, after playing the Song of Storms, but it's no where near as drastic as the changes at Snowhead. I can only imagine how elated those Goron's must be every time the curse is lifted.
This is arguably one of the most memorable snow area's of all time, and I can't wait to see how it turns out in the recently announced Majora's Mask 3D.