It's dangerous to generalize. That's why those articles in men's magazines...'What Women Want" are usually more confusing than helpful. Interview 20 women and you will get 20 different opinions about what is hot.
Having said that, a bodybuilder is an extreme of a certain type. Just like the skinny rock star is an extreme. I think that people out on the far fringes of the bell curve in any aspect of their attributes...physique, personality or behavior, will naturally have a small group of the opposite sex that finds them attractive. Very often however, those that prefer an extreme will be overly enthusiatic about it and that works to the bodybuilder's advantage. Women that like bodybuilders, REALLY like bodybuilders!
We also have to take into account the stereotypical, public PERCEPTION of the bodybuilder; stupid, narcissistic, poor, we've heard it all before and unfortunately, far too many bodybuilders do little to dispel that image. When a woman meets a bodybuilder that shatters those myths and is articulate, sensitive, funny, worldly and talented in venues other than the gym, the woman may find to her surprise that she actually LIKES a big, extreme physique because, you see, PERSONALITY still counts!