Learn a bit about electronics and hardware, so you can interface computers to the real world. You can learn about signal processing by playing with GNU Radio,

Learn a bit about electronics and hardware, so you can interface computers to the real world. You can learn about signal processing by playing with GNU Radio, which is kinda fun even if you're just working with the I/O from your microphone and speakers. Groking negative frequencies is kinda wild, but useful. Learn how to test backups, for real.