koan - 2:18 am on Sep 2, 2011 (gmt 0)
Dan01, I had better luck putting the noindex tag in pages when I tried to remove a large section of my site from Google's index. When I first used the robots.txt file, it was taking forever. I understand that doing it manually with each pages individually may not be viable though. Mine used a simple template page for all of them so it was easy.
Did it help with Panda? Not one bit, so far.