With the introduction of iTunes 10, several new and rather unusual UI changes have arrived as well. Perhaps the most troublesome, for me personally, have been the vertical window control buttons. I prefer consistency in all of my applications, so luckily a quick fix is available to restore the standard horizontal buttons.
Simply run the following command in your Terminal:
defaults write com.apple.iTunes full-window -1
Now, just restart your iTunes application and you should be all set. A special thank you goes out to Ars Technica’s Review of iTunes 10 for this information.