I'm always checking out bikes if I see someone riding around here, but when faced with a girl on a bike it's a tough call.
The site of anyone on a bike, outside of the weekend roadie group-rides, is pretty uncommon, a girl on a bike even more so. Since I'm single I'd probably check out the girl first, then the bike.

If she was on a fixed-gear I'd be stunned.
I'll occasionally see people cruising around during the warmer months, but Californians are wussies when it comes to cold, so cyclists are even *more* rare during the winter.
-Trevor