this page was helpful), I'd say I prefer women in the sizes 2-8 range. 8 is on the chunky end of the "healthy, attractive" range for me, but some women pull it off well. But size 10 seems to be the threshold where ALL the pictures start looking "pudgy" instead of "curvy" to me and really start falling fast in the sexy department. All of this is obviously just IMO. But I don't think I'm unusual in my preferences at all. The media does tend to unfairly glorify VERY thin women over women who are healthy and sexy but not quite as thin. But I don't think that's what's going on here, and I don't think that makes it unfair to say that if a "normal" American woman is size 14, then the average American woman is unhealthily and unattractively fat, KWIM?
Also, I think "fat Christina" above is more like a 12 than an 8. She's clearly wearing shape-control clothing and would look much bulgier in the middle without it.
EDIT: None of this is to say that we should poke fun at, judge harshly, or denigrate fat people. But I don't think we should pretend they're not fat either. Size 14 shouldn't be average.