Interesting responses, though I think some are confusing trendy/fashionable with just plain "popular."
I apologize in advance if I'm being prejudice, but I'm just stating what I see on the streets:
VW Jetta/New Beetle- Teenagers, females.
Scion tC- middle-class, asian females, some males as well.
Ford Focus- white, middle to upper class, female.
The TL seems to be quite popular around here too, but its a toss-up as to who it's fashionable with, as I see plenty of young and older drivers.
Escalade- Predominately young, African American or Hispanic drivers. But I rarely see any of these in my neighborhood, only in the lower-income parts of town.
300 with HUGE wheels- Again, predominately younger African American or Hispanic buyers, not sure why.
RX330- Middle-aged couples.
Popular?
Teenagers: Any 4-cyl Honda/Toyota family sedan, within the last five years. Trendy people aside, there are still quite a few Acura/Lexus models, but those are obviously hand-me-downs.
Families: Sienna, Odyssey, Pilot, MDX, and 4-cyl Honda/Toyota vehicles.
The six-cylinder Taurus/Malibus are also extremely common in the lower-income parts of town, but are driven predominately by African American or Hispanic drivers, age irrelevant. Again, not sure why. I think I see two or three of these in my neighborhood a year, but I can't go more than ten feet without seeing one in some parts of town that I frequent.