I'm not a big fan of the current trend in some quarters to universalize Jewish holidays, calling Passover the "Festival of Freedom," for instance, and then trying to apply its lessons to, say, gays suffering under the yoke of modern academia. (Put a purple ribbon on your office doorframe so the liberating protestors will know not to molest you.)
Passover is, in fact, the most Jewish-centric of our holidays. It's the holiday that commemorates when, under the pressure-cooker of a midnight escape, we became a people, a nation, rather than a rabble of slaves. It's the holiday where we leave tyranny for the — as yet undefined — servitude to God.
While the promise of our relationship with God is established by the covenant with Abraham, it's during the events of Passover that those promises begin to be fulfilled. (In fact, there's a tradition that the covenant with Abraham had been largely forgotten by the Jews - but not, of course, by God.) It's also the first time we experience events as a nation and not as a collection of tribes, although the tribal affiliations will continue until the present day.
Part of the Haggadah — the script for the Passover Seder — I believe emphasizes this particularism:
It is told of Rabbi Eliezer, Rabbi Yehoshua, Rabbi Elazar ben Azaria, Rabbi Akiva, and Rabbi Tarfon, who were reclining at the Seder in B'nei Brak, and had spent the whole night telling the story of the Exodus...
The irony is that of the rabbis in the discussion, all but one are either converts or descended from converts. The other is a Levi, and tradition holds that the tribe of Levi didn't suffer under slavery the way that the rest of Israel did.
This means that of the rabbis discussing the law, none of them actually had ancestors who were slaves. The fact that we read this story on Passover is significant because it implies that it's the Passover Story that defines us as a people. Having accepted this story, the Passover story, as their own, they (or their ancestors) became a part of the people. Not simply an act of faith, or a belief in the universality of God, but an act of identification with the Jewish people was necessary for them to be accepted. And these men, either converts or descendents of converts, became among the greatest of our Rabbis. (The similarity between conversion to Judaism and immigration to America is striking, but a topic for another day.)