My site was hit by Panda last July and has been going down farther with every Panda update (traffic down to about 20% of what it used to be). I was too busy working on other sites for several months to try and figure out what was wrong but I suspect it was overoptimiztion, which I've been trying to fix since march, to no avail. I'm still ranking high for non $ keywords but all my $ keywords are off the chart. None of my 50 client sites were hit by Panda. I only experimented with my own site!
I would apprecite it if someone can look at my site and let me know if they see anything that I should change.