I think by far the most poignant and memorable images among those (to me) are the ones of the mohawked punk in Germany, crouching and crying, and the woman in England with her hand through the gate.
Those'll stick with me for a long time.
In terms of poignant still images, the canadian paper The Globe and Mail had a really well done supplemental section on Wednesday last week. The cover picture was a 60-something year old man in his suit, a handkerchief over his mouth, and completely covered in dust. The entire image had this green cast to it, and it was such a good image I had find another copy of it (after giving my first copy to my co-worker). The back image was of ground zero, with the empty husk of one of the towers jutting up into the smoke, overturned ambulances and cars in its wake. Incredible stuff, makes me want to be a photojournalist very badly.
Good link, though. thanks.