I'm travelling to the states next week. I have a lot of pirated content (books and music) on my hidden encrypted partition on my laptop and external HD. Should I be worried, and what are my options if I do get stopped? (I'm actually a regular user - this is a throwaway account for obvious reasons).
I'm not an expert on this, but judging from the discussion above based on the EFF guide, it sounds like hidden partitions aren't recommended. The consensus seems to be that they may have ways of detecting hidden partitions and may ask you if you have any, placing you in a situation where you have to decide whether or not to lie to them. If you do, you could get busted for lying. If you don't lie, then it's the same as having full-disk encryption except it's slightly more suspicious and you'll be in the situation where you're not obliged to tell them the password, but they will take it into consideration in deciding whether or not to let you into the US.
I don't know how long you're planning to stay in the States, but it might be wise to bring an empty laptop and certainly not an external HD if it's for a short visit.