To add a clinical twist, there is a psychological study out there that talks about the 'most attractive' proportions in a male physique. Darned if I know how to find it now - but it is out there! There's science for you!
I have read an article on it as well the reason a lot of woman are so attracted to nice butt is actually a lot more animalistic then aesthetics it has to do with the mans thrusting abilities that has direct correlation with the shape and tone of the backside.
hmm, broad shoulders , gooooood pecs, defined back, hard round backside , verrrry tapered waist and good sized quads and big calves.
Now all i need is to find a pic and post it.