Identify a subject you think students should be banned from being discussing in a student newspaper.
You should apply the same standard to the speech you are banning that the supreme court told school administrators they should apply: The school should only ban speech when they believe the ideas expressed create a danger for other students, or for the atmosphere of the school as a whole.
I think that the topic areas should be as broad as possible for student newspapers. Yet, I would suggest that one area that should be dissuaded would be the attempt to post personal information about staff members online, such as addresses or incomes. I am not entirely certain that this needs to be banned, but rather discussed within the boundaries of "responsible journalism." In a school newspaper setting, there is a discussion as to what constitutes responsible journalism, usually led by a faculty member. I think that this is where discussion of topics such as refraining from publishing personal information and respecting the boundaries of confidentiality becomes a talking point. School administrators might not need to "ban" such practices, as much as monitor that the faculty involved with the school newspaper is presenting a discussion to students as to what constitutes responsible journalism and how the school newspaper, above all, must represent this.
It is a challenge in a society that is so free and able to access information. Director Spike Lee has demonstrated this, when he erroneously "tweeted" the home address of George Zimmerman. With such rapid platforms of social media, where information is more fodder than anything else, there needs to be constant and steady discussion as to what constitutes responsibility in reporting and ethical reporting. In a setting where the "iReporter" has become so common, suggesting that anyone and everyone is a reporter, and that the line between formal news organizations and anyone with a blog and a twitter account is blurred, students need to be reminded of this distinction and this can be done through a discussion with a faculty advisor, as opposed to a ban from school administrators.