This one and this are my favourites of your subway shots. It almost seems to me that you stood with your 10D hanging on the neck for over half a second to take this shot. Rush hour on subway there is quite intimidating...
Tami makes an excellent point here, Jen. All of us must face the world's problems collectively as well as individually. If ever there was a "collective" image, this is it.
I see something else in this picture Phil. The blurred shot shows that we are all connected to each other in some way as we travel through life. In this intimate physical setting each person's movement effects the next person, no man is an island.
Similar in meaning to the preceding shot, but this one is suffocating in its compression. These people are inches apart, almost intimate in physical presence, yet utterly unmindful of each other. Another remarkably expressive image with profound implications.