Jin: Probably a teddy bear, some chocolates and flowers.
Jimin: A movie marathon with him for a whole day.
Jungkook: Something you've been wanting for a long time, perhaps the album of your favourite band.
Suga: He'd take you out to dinner then when you return you cuddle in bed.(Best day if you ask me.)
Rap Monster: He'll take you to the cinema and you'd probably watch something like Avengers.
J-Hope: He may teach you how to dance.
Taehyung: Now, this muffin would want to get you something memorable, something like a necklace or bracelet that has 'Taehyung's Jagiya <3' carved in.