If you have any sensitive information on your laptop or other electronic devices, you may want to store it elsewhere when crossing the border, according to this article in Travel Weekly (free sub req'd). From the item:
The ruling prompted a warning from the Association of Corporate Travel Executives (ACTE) that corporations and their business travelers should limit the amount of proprietary data on laptop computers and other devices when travelers cross U.S. borders. It also warned that personal data, including photographs, finances and e-mail, are subject to examination by Customs and Border Protection inspectors.
Update: The Electronic Frontier Foundation is fighting this one:
In a letter sent to the House and Senate Homeland Security and Judiciary committees today, the coalition urges lawmakers to consider passing legislation to prevent abusive search practices by border agents and to protect all Americans from suspicionless digital border inspections.
"Our computers, cell phones, and other electronic devices hold a vast amount of personal information like financial data, health histories, and personal emails and letters," said EFF Staff Attorney Marcia Hofmann. "In a free country, the government cannot have unlimited power to read, seize, and store this information without any oversight."