Husserl is very important for Heidegger (who in turn is fundamental for Derrida). But you can probably read Nietzsche, being as he is chronologically anterior, without losing on context. Nietzsche is one of those authors who doesn't really have much of a technical vocabulary, and the one he does have is seldom kept beyond the one book he may be using it at the time. He is obviously more than fundamental for those philosophers you're mentioning, but not for technical usage of terms, I'd say.
Instead, what might prove fundamental is Hegel. But then you have to read Kant, and Leibniz, and Spinoza, and Aquinas, and Plato and oh where does it end?!