As the mornings and evenings are looking a bit darker, I thought I would take another look into visibility (pardon the pun, there). The Xtracycle, being my primary ride now, has the most reflectivity. The FreeRadical has two reflectors on it. I wrap two reflective bands between the V-Racks and the Schwalbe tires also have reflective sidewalls. Below you can see what it does when the camera flashes.
Some mornings (and most nights) I throw on the dorky reflective vest, too. All this reflective gear paired with a blinky light clipped to my waist make me pretty visible.
I would say that if someone doesn't see me, it's because they're not looking. I used to underestimate the value of reflective stuff. I thought it had to be done with some sort of light emission, not reflection. Obviously, this works. I don't like covering my bike with reflective tape (for aesthetic reasons), but these bands, Schwalbe's tires and Xtracycle's built-in "tail lights" make a huge difference.
Get out there.