As someone who has studied and taught computer science in three different universities in three different countries (and therefore three different educational s

As someone who has studied and taught computer science in three different universities in three different countries (and therefore three different educational systems— France, UK, US), I can tell you from experience that you won't learn hacking by being a CS major. As a CS major, you will learn a various amount of "theory" and "physics" (to reuse pg's terminology) depending on your university (for example, the university in France where I did my undergrad had a lot of mathematicians amongst professors, so we had a lot of math + cs theory classes, whereas some of my friends elsewhere had more EE-style courses). But no "hacking". You will learn the hacking part by hanging out with the kids who like to code, grad students in the labs, by working on open source projects in your spare time, etc. — but one needs not be a CS major to participate in those. If I had to start again, I would probably choose to study mathematics or philosophy. CS is a fascinating topic, but the way it is taught is antiquated, and it is one of the easiest topics to teach to oneself. Of course, this is all based on my own personal experience, so it is a completely subjective opinion.