I've been increasingly finding that as I'm going along the street, I'm constantly checking out all the bikes I see, locked up to rings or cruising down the road.

I first look at the type of handlebars from a distance to grab my attention. If they are drops my attention is piqued, if they are bullhorns even more so. I check to see if there are brake levers on, and if so, what kind and how many. If I can't see any brakes, then its settled, and I stop and have a look at the bike (meaning its either fixed or a coaster brake, but most bikes sans-brakes and with drops tend to be fixed gears) .

After that I immediately look at the chainline. If its got a derailleur I tend to move on. Even on crappy coaster brake bikes I seem to appreciate the rounded pie slice shape of the chain.

Sometimes I'll see some hardcore looking messenger or the like going about his business and I'll notice a straight chainline and think 'cool', then I see his legs stop spinning and think "pshhhht... singlspeed? come on!"

Its gotten really bad, and my friends have been starting to catching me checking out bikes now. Its become sort of an inside joke.

Anybody else cheat on their bikes with their eyes?