The book "Cracking the Coding Interview" is a huge help for getting through interviews. It's a real grind to work through, but worth it. You don't have to do all the problems, but make sure you do some from each section.

Most business degrees can be useful, because you understand the business much better. Accounting actually turns out to be useful for distributed systems.

Edit: It wouldn't have occurred to me, but I think Anthropology would be very helpful in understanding why systems were put together the way they are.