What I think are interesting are the "accidental" self portraits, those that produce an image, sometimes eerie, of the photographer.
The first 2 below are like this. Sorry, I can't find the original of the first.
The third below is the original of the one I used to make the current avatar. This is a reflection in Cloud Gate, the sculpture that has aroused quite a bit of controversy over the past couple years. I have another avatar from this as well, one scanned at max res which gives an almost recognizable self portrait. 🙂