I have been watching men watch. On the roads. And in random order, these are what they like to watch
-Women (city roads, peak hour and all those bike-dudes seldom look at the road)
-Bikes (there is this Chennai dude who is a frequent sight on his Kawasaki ZX series and he ALWAYS gets envious stares)
-Cars
-Reflections (theirs. On any reflective surface they chance upon)
-Smart Men (this happens with a greenish pallor. It would probably qualify better for 'sizing' rather than 'watching')
-Buildings (if it is a macho building then the look offers appreciation. If it is a purplish orange or some other such gaudily created building, the look mocks. Along with the mocking look, I actually heard one guy say, "Must have been designed by a woman")
-Traffic Lights (not much choice on this one!)
The more evolved ones also take a look at the sky, the greenery and even pavements (I actually mean the pavement and not the bipeds on the pavement).
Those would be the top ones, qualified so, on the basis of sheer frequency of occurence. Now, if I were to name the top one, I would have to give it to the bikes. Pretty women, step aside please. Bikes are hotter.