I see conservatives and libertarians of various stripes quoting Ayn Rand fairly often. Some of these people are also Christians. I would think (and hope) that (at the very least) Christians would want to avoid quoting too much a professed atheist who called C.S. Lewis an "abysmal bastard," in marginalia. As for non-Christian conservatives and libertarians, neither would disqualify her necessarily. However, how about the fact that she is a terrible writer and thinker - there is nothing in her writing that cannot be found better and more carefully discussed elsewhere.
To back up that last statement, I present to you a list of authors and thinkers who said many of the same things as Rand, but who are so much better thinkers and / or authors. Read some of their works - discover better statements for the same ideas and new ideas with good statements. Thanks to the Online Library of Liberty for the quotes.
However, before proceeding into the quotes, I should note that there is considerable overlap between classical liberalism and libertarians in the United States. Many libertarians are more classical liberals (who aren't aware of tradition) and many conservatives, libertarians or classical liberals. There has been much ink spilled over the precise delineation between conservatives, libertarians, and classical liberals, and the lines even now are not quite clear.
J.S. Mill - The object of this Essay is to assert one very simple principle, as entitled to govern absolutely the dealings of society with the individual in the way of compulsion and control, whether the means used be physical force in the form of legal penalties, or the moral coercion of public opinion. That principle is, that the sole end for which mankind are warranted, individually or collectively, in interfering with the liberty of action of any of their number, is self-protection. That the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. … In the part which merely concerns himself, his independence is, of right, absolute. Over himself, over his own body and mind, the individual is sovereign. - From On Liberty - 1859
F. Hayek (considered both classical liberal and libertarian): This particular function of government is somewhat like that of a maintenance squad of a factory, its object being not to produce any particular services or products to be consumed by the citizens, but rather to see that the mechanism which regulates the production of those goods and services is kept in working order. Law, Legislation and Liberty, 1973.
For more examples, and excellent and intelligent discussion, see the Introduction to Libertarianism, here.
For Classical Liberals:
Ludwig von Mises: To be sure, in the customary rhetoric of the demagogues these facts are represented quite differently. To listen to them, one would think that all progress in the techniques of production redounds to the exclusive benefit of a favored few, while the masses sink ever more deeply into misery. However, it requires only a moment’s reflection to realize that the fruits of all technological and industrial innovations make for an improvement in the satisfaction of the wants of the great masses. All big industries that produce consumers’ goods work directly for their benefit; all industries that produce machines and half-finished products work for them indirectly. The great industrial developments of the last decades, like those of the eighteenth century that are designated by the not altogether happily chosen phrase, “the Industrial Revolution,” have resulted, above all, in a better satisfaction of the needs of the masses. Liberalism, The Classical Tradition, 1927.
John Locke: And the zealots hardly have patience to refrain from violence and rapine, so long till the cause be heard, and the poor man be, according to form, condemned to the loss of liberty, goods or life. Oh that our ecclesiastical orators, of every sect, would apply themselves, with all the strength of argument that they are able, to the confounding of men’s errours! But let them spare their persons. Let them not supply their want of reasons with the instruments of force, which belong to another jurisdiction, and do ill become a churchman’s hands. Let them not call in the magistrate’s authority to the aid of their eloquence, or learning; lest perhaps, whilst they pretend only love for the truth, this their intemperate zeal, breathing nothing but fire and sword, betray their ambition, and show that what they desire is temporal dominion. - Four Letters Concerning Toleration, 1685
Edmund Burke: I have defended Natural Religion against a Confederacy of Atheists and Divines. I now plead for Natural Society against Politicians, and for Natural Reason against all three. When the World is in a fitter Temper than it is at present to hear Truth, or when I shall be more indifferent about its Temper; my Thoughts may become more publick. In the mean time, let them repose in my own Bosom, and in the Bosoms of such Men as are fit to be initiated in the sober Mysteries of Truth and Reason. My Antagonists have already done as much as I could desire. Parties in Religion and Politics make sufficient Discoveries concerning each other, to give a sober Man a proper Caution against them all. The Monarchic, Aristocratical, and Popular Partizans have been jointly laying their Axes to the Root of all Government, and have in their Turns proved each other absurd and inconvenient. In vain you tell me that Artificial Government is good, but that I fall out only with the Abuse. The Thing! the Thing itself is the Abuse! - A Vindication of Natural Society, 1756
Michael Oakeshott: This, I believe, is the appropriate image of human intercourse -- appropriate because it recognizes the qualities, the diversities, and the proper relationships of human utterances. As civilized human beings, we are the inheritors, neither of an inquiry about ourselves and the world, nor of an accumulating body of information, but of a conversation, begun in the primeval forests and extended and made more articulate in the course of centuries. It is a conversation which goes on both in public and within each of ourselves. - Rationalism in Politics, 1962