Since the establishment of the state of Israel, religious Jews of Zionist persuasion have struggled to create a liturgy for Yom Ha-Atzmaut (Israeli Independence Day). The most widely observed religious custom for Yom Ha-Atzmaut is the recitation of Hallel, based on the Talmudic injunction that Hallel be recited when the Jewish people is delivered from distress (Pesahim 116a). To add anything more, however, entails finding a traditional paradigm suitable for a modern holiday, and there is little agreement as to the appropriate paradigm.
One early model, suggested by Yom Tov Lewinski, was for Yom Ha-Atzmaut to be observed in a manner similar to that of the festivals mandated by the Torah (Passover, Shavuot, and Sukkot), with the lighting of candles, cessation from labor, recitation of kiddush, and the insertion of ya'aleh veyavo into the amidah prayer and the blessing after meals.* It was not to be, however; Orthodox Jews were reluctant to give a modern holiday the status of the ones in the Torah, and the national celebrations that eventually developed in Israel were incompatable with the traditional festival restrictions. Another model is based specifically on Passover, and includes readings from a haggadah retelling the story of the modern-day redemption. A number of haggadot have been composed for Yom Ha-Atzmaut, but none has gained widespread acceptance, perhaps in part because the atmosphere on Yom Ha-Atzmaut in Israel is so incompatible with a family seder.
Some of the liturgies currently used for Yom Ha-Atzmaut are not based on any particular paradigm, but these can seem a bit random and therefore lacking in force. The Israeli rabbinate, for example, authorized the recitation of certain psalms and the reading of a selection from the Prophets, but not from the Torah. A service that I heard in college consisted of an odd hodgepodge of texts taken from sources as diverse as kabbalat shabbat (the Friday evening service) and Naomi Shemer (a modern Israeli songwriter). The Reform movement has its own service for Yom Ha-Atzmaut, comprised mainly of original compositions -- fine for people who like that sort of thing, but again, I think it lacks force.
It seems to me** that the most reasonable liturgical paradigm for Yom Ha-Atzmaut is that of Chanukkah and Purim. Since these holidays comemorate events that occurred after the composition of the Torah,*** they don't have the status of the major festivals (which means fewer religious restrictions), but they do have their own liturgies including readings from the Torah and Prophets, and they are accomanied by a generally festive mood. The main liturgical innovation for Chanukkah and Purim was the al ha-nissim prayer, which thanks God for delivering our ancestors from their enemies. Versions of al ha-nissim for Yom Ha-Atzmaut have been composed for the religious kibbutz movement, the Conservative movement, the Masorti movement, and the Israeli Reform movement. (Yehonatan Chipman has a number of the texts with insightful comments. Avraham Hein adds the version from the Conservative Siddur Sim Shalom.) Communities that recite al ha-nissim generally also have a Torah reading (Deuteronomy 7:12-8:18 or 30:1-10) and a Haftarah (Isaiah 10:32-12:6).
Certain problems inevitably arise when a preexisting paradigm is applied to a new situation. The various versions of al ha-nissim, for example, all use the language of the al ha-nissim for Chanukkah, which describes a battle in which the "wicked" are delivered into the hands of the "righteous." (The Reform version substitutes "members of your covenant" for "righteous," which is a bit better. The Sim Shalom version uses "guilty" and "innocent" in its "translation," but the Hebrew is the same as in the others.) Now, there is no doubt in my mind that the Israeli War of Independence was a just war, but that doesn't necessarily mean that all the aggressors were "wicked," and it certainly doesn't mean that all the victors were "righteous." The Torah readings open with the same implication of Jewish righteousness, and one of them (Deut. 7:12-8:18) becomes more problematic as it proceeds: "You shall destroy the peoples that the Adonai your God delivers to you, showing them no mercy . . . You shall cast the images of their gods into the fire" (Deut. 7:16, 25). The choice of Haftarah, meanwhile, seems to have been motivated by the view that the establishment of the state was the beginning of the messianic era, which I find troubling on a number of levels. (Admittedly, the Haftarah doesn't have to be read in that sense in this context, but it would not have been my first choice.)
In spite of all this, I am not inclined to diverge from the existing liturgies. Chanukkah and Purim were controversial in their times precisely because they were new, but they eventually gained the acceptance of the Jewish community as a whole. I don't know what it would take to achieve the same degree of acceptance for Yom Ha-Atzmaut as a religious holiday, but some semblance of a standard liturgy couldn't hurt.
*Rabbi Irving Greenberg, Living the Holidays (New York: Simon & Schuster, 1988), p. 388. Greenberg references Lewinski's Sefer Hamoadim, vol. 8, Y'mai Moed V'Zikaron (Tel Aviv: Dvir, 1956), p. 486.
**Yehonatan Chipman agrees.
***Whether Purim actually comemorates an "event that occurred" is not really relevant here; clearly, those who composed the Purim liturgy believed that it did.