As a former Randian and current philosophy professor, I think it's important to warn the world that she does indeed make crucial errors. Lots of them. She was definitely brilliant -- to this day, The Fountainhead is one of my two favorite books -- read it if you haven't! But beware the *philosophy*.
Here's one important mistake. A lot of the time Rand misunderstands her own moral and political justifications. She has genuine insights but mistook what they were. For instance, her defense of egoism and laissez-faire capitalism is often consequentialist. That means, the justification she offers for acting egoistically and adopting a laissez-faire capitalist system is in terms of the positive overall outcomes of doing so. Perhaps we could allow that in general she speaks as if egoism and l-f benefit primarily the community in which they flourish, though she definitely thinks that these are the right values for human beings in general, if they live in anything like a modern community. A good chunk, perhaps more than half, of Atlas Shrugged is devoted to making this point. It isn't mere backdrop that the world is falling apart. (Think also of For the New Intellectual.)
All along Rand plays up the positive consequences of egoism and l-f. But she speaks as if what's thus justified is a total, unlimited commitment to those things. That is, it is *always* morally right to act egoistically and l-f should be total, 100%, nothing beyond military, police, courts, and the necessary infrastructure for those functions. And no taxes whatsoever. Rand can say, for instance: *always* act in your own (rational, long-term) self-intereste, *never* take property -- but then she justifies that claim by reference to the positive consequences of doing these things.
Two questions thus arise: first, are there any cases in which it is just *false* that being egoist or adopting unlimited l-f has the best consequences? (It seems to me, frankly, that there are *plenty* of such cases!!! They are the norm, in fact!!! But notice this is purely an empirical question on which I, as a philosophy professor, have no claim to expertise, though I do read a lot.) Second, in such cases, if there are any, *what*'s justified? To act egoistically or adopt l-f -- or to act non-egoistically or limit capitalism in some way? Rand has given us no reason to think that in *these* cases, egoism or l-f capitalism is what's justified. Or at least, insofar as her justification for egoism and l-f in the other cases was the very fact that they did have good overall consequences (a lot!), she's given us no reason to draw her desired conclusion in these cases.
It seems obvious that Rand was scarred by Communism and her ideas rigidified to some extent. In that sense, her convictions were held as if religious (and, like most or all religions, there is much truth in what she says). (Inordinate fear of "creeping socialism" -- which makes the only option to pure capitalism seem terrible -- is of course not unique with Rand. In fact, I think it's much of what makes sincere Conservativism possible. But Rand really took it to special heights.)
Of course, I recognize that Rand says all that stuff about life and choice between existence and non-existence and stuff. Well, that's all just crap, frankly -- here I *do* have expertise. I don't have time to write about it now, though I hope to one day, since it is important (there are many more Randians than is commonly recognized, since you can't really publicly admit the extremity of your views -- although Rand herself would say you should, I think). But take it from me -- whatever truth there is in what Rand wrote with respect to her explicit philosophical defense of egoism and unlimited l-f capitalism falls far short of those claims (that those things are *always* right). Rand set out to supplement her genuine insights (much of which were about the productive invisible hand of capitalism, a fact which even liberals acknowledge) with a philosophical foundation, but her foundation was not only spurious (justified nothing, in fact) but misleading: she thought she'd proven something which went way beyond those insights. She thought she'd proven a kind of Absolutism about egoism and laissez-faire capitalism. (I'm tempted to say: "and you want to see the results? look all around you!")
I'm a consequentialist philosophically (yay to Mill, Sidgewick, Moore, Parfit, Brink, Singer and the rest, though read Glover's Humanity for some warnings) and a liberal politically (yay to all the [genuine] bleeding hearts out there) and nothing Rand says makes me doubt those commitments, though I've absorbed her lessons thoroughly, many years ago in fact.