I like AV star with slender type of body with A-B sized boobs. Most JAV fans I know off prefer bigger boobs but I prefer them to be a handful. Flat tummy is the best and cute face is a bonus. A few examples of my favourites:
Minami Aizawa
Kana Momonogi
Iori Kogawa
Tsumugi Akari
Moe Amatsuka...