The Pixie - Longer layers have enough weight to keep hair in place while shorter layers add volume all around the head.
The Bob - The defined shape of the bob, whether you get the look without or with thin bangs, adds the appearance of volume.
The Choppy Bob - This can be worn short or long. The angled layers add texture and volume to fine hair.
Long - Shoulder length hair is a universally flattering look so a good length to end with for thin hair.