Mac OS X 10.9 Mavericks
sudo rm -rfv /Library/Caches/com.apple.iconservices.store; sudo find /private/var/folders/ \( -name com.apple.dock.iconcache -or -name com.apple.iconservices \) -exec rm -rfv {} \; ; sleep 3; killall Dock; killall Finder
(all on one line in Terminal.) Use this in case Finder or Dock display strange or generic icons where they should not.