I wouldn’t think that my list of favorites would be helpful toward a serious study of Philosophy as an established discipline. My suggestion is to read the classics. Still, read the really “Classic classics” and not just a general assortment of old works; that method tends to develop incoherent thinking.
Remember that academic disciplines tend to be in a state of flux; they change through time, and so that which is most relevant can change from era to era. Those works colloquially called “the classics” tend to be classics not because they are old (though in philosophy as in wine, generally “the old is better”) but because they stood the test of time.
Standing the test of time is a very important, but undependable test, which is why though everyone in a discipline recognizes the usefulness of time tested works, they are rarely described in this way. While the works of an Augustine stood the test of time because of their ever returning trans-epochal value and ability to speak to issues that transcend time and culture, there are many others that are still with us that seem to lack much beyond “historical” value, or merely the value of being old.
The differences are difficult to narrow down to an identifiable measurement, but we could think of it like this; though the works of Augustine are more than a thousand years old they are still read anew in every generation, speaking in ways that people understand, and still having a transformative effect upon their persons, while at the same time, just more than a hundred years or so ago, there were hundreds of thousands of passionate Hegelians, some forms of dogmatic rationalism holding a powerful sway over the universities and intelligentsia, while now they are seemingly extinct, and yet we still must read Hegel in order to understand our own era, because of his massive influence upon getting us from there to here.
Plato and Aristotle have the same effect; in a hundred years perhaps no one will be reading Quine, or Wittgenstein, or Rorty but I think we can say with a reasonable amount of credibility that as long as people study philosophy, they will be reading Plato and Aristotle, and in theology, without such an acute sureness, Augustine, Aquinas and Calvin.
So if you really want to start studying (P)hilosophy, start with the Major majors, because by the time you get a solid footing in their thought, (it is after all the bulk of the labor of doing philosophy) all of the other questions about what to do and how to do it should begin to answer themselves.