What is it when you know you cannot define existence without using something based IN existence? On another forum a few years ago, there was a similar thread arguing reality. Is reality real? The thread covered other permutations of that, like "How big are we", which broke down into "is our universe a particle orbiting the nucleus of an atom in another universe" and such. It is fun to philosophize, but Ann's perspective seems rather bleak and wanting IMO. Very narcissistic and self-centered. The very nature of social animals like primates is the capacity to be family/group centered and NOT self-centered.
Rand was lacking in certain aspects of her philosophy the further down the line you go into it. For instance, she never had children and I think that showed in the dearth of philosophical commentary in regards to children and family.* It also was a glaring hole in her fictional characters lives; the vehicle through which she presented her philosophy in her novels. Everyone in her novels was conveniently sans children, hero or villain they didn't have kids. She makes a passing comment about a female character in
Atlas Shrugged who has kids in Galt's Gulch but it amounts to nothing more than saying that this non-character's children were happy and healthy (due in no small part to being raised as Objectivists, go figure). The details of how this character successfully mothered her children were conveniently lacking though.
One has to wonder at the amounts of birth control the women in Rand's novels gobble up. I think it's put into the municipal water supply or something the way no one gets pregnant despite having copious amounts of sex (usually rough sex, Rand had a thing about that for some bizarre reason).
At any rate, the point here is do we exist and I posit that Rand's epistemology, her theory of knowledge, is correct in that we have to exist first in order to even ask the question of do we exist. People can say what they want about other aspects of her philosophy but for them to try and claim that she is wrong about existence preceding consciousness is just laughable (and sad if you think about it).
As for the originality of her philosophy in toto, well, she based a huge chunk of her philosophy on Aristotle's works ("A is A" for instance), although certainly not all of her philosophy, but at least she gives him credit. She was also heavily influenced by Freidrich Nietzcshe whom she doesn't give much credit to at all. She claimed to reject him but early drafts of
The Fountainhead and notes from her journals prove that she was pretty much cribbing his concept of the superman. She toned it down in the final drafts of the manuscript but the evidence remained nonetheless and was published posthumously for all to see (she kept all her notes and journals and scribblings). Same with her novel
We the Living, which originally was published with a draconian Nietzscheian bent replete with characters spouting some pretty horrific stuff if I recall correctly (I might be wrong, she might have edited it before publication the first time but I'm pretty sure it made it to at least one printing). She revised the novel and cut out those blatantly Nietzscheian elements at some later point.
So, yeah, she can definitely be criticized on certain aspects of her philosophy but as I stated earlier her tenet of the Primacy of Existence is unassailable. Existence exists and consciousness and identity proceeds from there. There literally can be no other way to run this equation.
*
The Simpsons episode in the first or second season with Maggie at the Ayn Rand day care center was pretty funny because it played on the unlikely combination of Rand and child care. They did a Maggie/Rand episode more recently where Maggie plays a Howard Roark type character (voiced by Jodie Foster) but it wasn't as funny as the first Rand episode. Not surprising as we all know that
The Simpsons was much funnier in the early days.
That was a pretty blatant misrepresentation of Rand's ethics as proven by the fact that it wasn't even a quote of hers. Low blow Joelist, low blow. 
