Once, while looking over photos, my friend pointed out to me that I've never been with a girl who didn't have huge boobs. The funny thing is, I normally don't even notice a girl's boobs when I'm getting to like her. I must do it subconsciously.
Anyway, I personally prefer girls who aren't super slim. Broomstick women just don't appeal to me so much. A couple of my girlfriends have been what some people would probably regard fat girls. I wouldn't rule out being with quite a skinny girl, if we were getting along and everything, but it generally just isn't what attracts me, so it hasn't happened yet.
I dunno if anyone would back me up on this, but to me, being hot has more to do with looking in proportion than looking slim. Small girls with absolutely ginormous boobs would look kinda silly. And a girl with a bigger build can actually be carrying quite a bit of weight, but as long as it doesn't LOOK out of place on her, as long as she still has a nice, shapely, feminine build (I'm not sure how to describe what I mean), it'll still look hot.
I guess you could take all this to mean I'm not overly fussy, though I don't particularly like wafer thin girls, which means the stereotype of guys wanting thin girls doesn't really apply to me at all. But at the end of the day, I'm never gonna be into a girl if we don't have some things in common, if we can't just talk shit and laugh and chill around each other, if something doesn't click between us. So yes, it is more about personality.