Add me to the list of concerned users -- I am responsible for a school installation of 300 computers (mostly WinXP), and find this little bug quite an irritant. It contravenes my teaching to students about the wonders of Apple: I tell them that Apple's secret to success is attention to both overall usability and the detail of the user experience.
This apparent presumptuousness -- or, worse, mistaken coding -- in bypassing Windows' rules on screen maximizing behavior is worrisome.
Or maybe somebody will explain that Apple is actually following true standards, but Windows does not really follow its own standards for maximizing screen display? Even so, iTunes needs to play well on Windows platforms.
Fix it, please.