I generally like long and straight, but do not mind the bottom to be curled. It mostly depends on how the hair looks on the girl. I have seen really pretty and cute girls in pony tails, and at the same time I have seen really attractive girls with short hair.
Long and completely straight (or wavy at the bottom). I also really like that new teenage trend where the hair is swept across the forehead. Savannah Highnote has perfect hair, so you can use her as a reference lol.