I hear that! Nice macro, although I think more diffused light might have brought out the detail without the harshness the sidelighting produced. Funny that the one penny on the UR hotspot is right side up.
Nice shot -- I think this would be really cool printed HUGE. I recently shot some coins myself for a project, and I know that the lighting can be a pain. (I wonder if it might be easier to shoot "older" pennies that aren't so shiny...anyway...) Those highlights are really hot, I wonder if it's possible to tone them down a bit. Hard call to make though, because they are important for helping define edges, so I don't know.
Composition- No paticular center of interest. Makes you take it all in at once. Background- Use of layers for background interesting. Technical- Very good, perfect exposure and focus. You obviously took a lot of care in placement of these pennies. Overall Impression- Nothing here to draw you into this picture, while its technically very good, the subject is lacking something, meets the challenge well. I like the way you not only placed the pennies tails up, but they are all facing different directions, so no matter which way you turn this some of them are upside down.