Comment Legality? CD music yes. DVDs (strictly speaking)No (Score 4, Informative) 285
Vanderhoth is dead on. Ripping a DVD is against the law in the US. The Digital Millenium Copyright act expressly forbids breaking encryption to access content. There are exceptions for security researchers. That said, DVD ripping by ordinary individuals for format shifting and back up is not prosecuted in and of itself. Share the stuff? You can get in all kinds of legal hot water. Lawsuits and prosecution.
Ripping a non-copy-protected Red Book cd that you own is perfectly legal -- provided you do not share the file. No encryption. No crime. First sale doctrine applies.
I travel to and from the US from overseas frequently. Only once in 20 years was I ever polled concerning the contents of my laptop. The US Customs agent asked me if there was any x-rated material on it. I answered truthfully that there was not. He was trolling for a demeanor hit and would have probably looked at my content for illegal porn had he not been satisfied by my confident negative answer. By the way, having even US-legal porn on the laptop can still get you in big trouble in the Middle East so be aware. Even silly rags like Maxim are trouble. Also mind what you eat, kids. Traveling to Dubai? Skip that poppy seed bagel in Sydney airport.. Really.
Bottom line, however? The posters are generally right. US Customs is not concerned about the technically illegal DVD rips on your hard drive. They probably would do nothing even if they found them. But, and here's the thing. If you are going to feel guilty and worried about that questionable content then leave it behind. You will ruin your flight. Your nerves might show as you cross the frontier and draw unwarranted attention. The fact that you even asked this question shows that this is a source of anxiety for you. You have your answer. Go in peace. Walk in beauty.