Niall: Shirts. Yes, your boyfriend is the corny type. He picked them out while on tour, and thought they were the best things ever.
Zayn: Necklaces. Not the average sappy crap, just a simple pendant you wear arround your necks everyday with eachothers initials.
Liam: Teddy Bears. A bear that you could give a squeeze whenever you missed him too much, and vice versa.
Louis: Mugs. Yours says "goodmorning beautiful" in his handwriting, while his says "goodmorning handsome" in yours.
Harry: Tattoos. Nothing too crazy, just a simple heart on the inside of your wrists. Yours was done by him, his was done by you.