Well Since I can't really Explain in numbers I'll show you pictures.
Too skinny, wouldn't want a date with her just like I wouldn't want a date from a overweight girl.
link Notice how this girl, her stomache is toned although you can really see bones. Also he arms it's as if there is no meat there either? It's obvious she's starving herself and this isn't attractive to me, also she has no boobs because of this either.
This girl is average. Now personally this is My favorite girl out there. This is the one that is the most appealing on the eyes to me body mass wise. This pic is from myspace of a girl I don't even know, although it is the best one I could find to describe middle/average/medium to you.
link Notice the Slight belly, not alot, but some But she's not skin and bones and total rock hard abs. Just your everyday girl. This is medium/normal and what I look for in a normal/average girl. Notice her boobs aren't DD's or anything, they might be like a B-C cup at most but that is just right honestly. Anymore pudge than this, and to me a girl is crossing the line. Much more and you become what we guys call."Borderline." Which means your a little too much pudge, but your not quite fat. Although a girl like this would be more appealing than a "Borderline" girl would be to me atleast, and some of my guy friends. Also notice she looks like she has a little bit of a butt, although it's not overwhelming, its inbetween the two extreme's of above this and below. This is average.
Now This girl has a weight issue. This is a Fat girl. Although, I also got this picture from myspace, and in doing so I kinda liked her personality. She did interest me because of who she was and how cool she seemed, so does it matter YES Size of a girl definitely matters in a first opinion or glance. Although Just like girls say about penis size it can be overlooked if you have enough other good qualities/traits/attributes. This isn't easy to do, and is rare, but I know see how it couldl occur, although probably wouldn't go for her. Although she does seem like a nice girl.
link Notice the chipmunk cheeks. The huge bicep's. The massive forearms, this gurl has bigger arms than I do. Now this is overweight. At least to me. She doesn't even show her bottom half probably due to the fact that her calves are the same way it always seems to go that way, if her arms are huge so are her thighs. So know you know what a guy looks for in a girls weight feel privileged.