At first, I worried that some people's feelings may be hurt by this poll. However, I have enough faith in this community to believe that there will either be a wide range of answers, or that a lot of people will pick "It doesn't matter, as long as they're healthy!" or "It doesn't matter, as long as they're happy!"
I ask because I am recovering from an eating disorder, and I have strived for so long to be as thin as possible and dreaded being "fat", but I like women of all sizes. I have enjoyed sex with obese, overweight, muscular, skinny, and underweight women, and I have loved them all. I have very different standards for myself than for other women.
So many women are fooled into thinking that they are not attractive if they are not thin, but I never believed that. I think that different people have their own preferences, while some just don't care at all. There is no single 'attractive' prototype.