I like thin girls best. Very thin girls, at that. Thin as a rail. Bones you can see. Technically underweight.
But experience has shown me a lot.
I've come to like and be attracted to plump girls too. Not truly obese girls, so far, but certainly plump and heavy. Or as we call them now, mushy.
My best example is Gaga. She is overweight and has what in an adult guy would probably be called a beer gut (only she doesn't drink, and her skin is much softer). She is still very, very sexy in her size and shape. And I wouldn't even imagine her not being overweight. Yes, I'd probably end up liking her better if she was skinnier, but I wouldn't change her. She is great mushy like she is. And oh, she can sit next to me or sleep next to me, I won't tell her she can't!
(Also, in her case it's clearly something with a lot of genetic influence. She exercizes more than most kids, and she eats rather balanced: she isn't too much into veggies, but neither is she too much into carbs and sugars as most kids her age are.)
So, speaking only for myself, skinny girls rule, but mushy girls will not be turned away when they show up.