I've read a fair bit of philosophy over the years with a particular interest in phenomenology and existentialism. I'll just go ahead and give you a list of my must reads:
Etienne Gilson - The Unity of Philosophical Experience, this is hands down one of the best commentaries on philosophy as a whole, I cannot recommend it enough
Heidegger - Being and Time, Nietzsche (4 part lecture series)
Nietzsche - Beyond Good and Evil
Aristotle - Metaphysics, Politics
Plato - Dialogues
Sokolowski - Intro to Phenomenology, great summary of the movement and that which lead to it
Safranski - Martin Heidegger: Beyond Good and Evil, probably the best biographical commentary on Heidegger's school of thought, another book I cannot recommend enough, wonderfully written, anyone with an interest in history should really get a lot out of it.
There's obviously a lot of other stuff out there but I'd say this is a good getting your feet wet list that still contains texts the seasoned reader would find useful.