Yossi Klein Halevi and Matthew Wagner have both written lately about the remarkable relationship between Chabad/Lubavitch and secular Israelis. Unlike other ultra-Orthodox sects, which all coldly reject both the state of Israel and secular Israelis as betrayers of Jewish law and observance, Chabad considers itself a kind of internal missionary organization, winning over secular Jews to piety through good works and generosity.
Unfortunately, Chabad's missionary service is rooted in essentially the same messianism as Christian missionaries': they believe that winning Jews back to observance hastens the coming of the Messiah. Ultimately, that motive can't sustain a generic service ethic, because it inevitably draws the missionaries towards more susceptible recruitment targets, such as the poor and the distressed. (Christian missionaries, for example, certainly follow this pattern.)
It's possible, though, that Chabad (or perhaps an offshoot, or a rival sect) could gradually evolve its beliefs in a way capable of sustaining its passion for serving fellow Jews in general. All it would require is a subtle shift away from believing in the need to convert all Jews to its brand of piety, and towards believing in its members' need to maintain its own brand of piety--including its practice of helping all Jews--as an end in itself.
I believe that such a shift would be of enormous benefit to the Jewish people. For the truth is that the fanatically observant, the fanatically secular, and the broad spectrum in between are all parts of a far stronger whole than any single one of those groups would be on its own. Other religions have discovered this, and typically maintain a pious class--priests, monks, monastics, and so on--that is respected for its dedication and service to its correligionists, but understood to coexist with a more worldly majority, rather than rejecting it.
Already, ultra-Orthodox Jews in general act as a kind of priestly class among Jews, devoting themselves entirely to study and piety at the cost of living on charity, and typically in poverty. They also perform a number of purely religious services to the community, such as recovering bodies for ritual burial (most famously after terrorist attacks). Unfortunately, rather than consider themselves a kind of spiritual elite serving a larger Jewish nation, they tend to view other Jews as apostates doomed to drift away from Judaism towards paganism of one kind or another. And of course, they denounce the state of Israel as a secular travesty.
That's strange, because the Jewish religion itself provides an admirable model for a "spiritual elite", rejecting both militant proselytizing and cultish insularity in favor of the role of duty-bound "light unto the nations". If only the ultra-Orthodox were to embrace that role themselves, they could become as valuable a resource for the Jewish people as the Jewish people have proven, time and again, to be for the entire world.