On the other hand, the form of a naked woman is complete proof that there is a God.
Hallelujah, brother.
Having said that (and knowingly anticipating all the "dude you're so gay" comments), I'll admit that I admire a well-developed male form as an artistic achievement without having any sexual attraction to it. The body of a trained athlete has a form and symmetry to it -- a beautiful solid strength like that of a good horse, or a great piece of architecture, or a great photo of Yosemite's half dome.
And at the gym, I secretly admire those guys who are in great shape. (Not the 'roid freaks, but the guys who look like they could play safety for a college football team -- it's a very different physique.) Sadly, there are enough mirrors around the gym to remind my short flabby pasty-white little self why I've earned that inferiority complex.
Which is why I stop looking as soon as we're in the locker room. There's only so much humility a guy can take.