While I'll freely admit the internet has already pounded the joke into the ground—the internet pounds every joke into the ground; it's what the internet does—Romney's awkward phrasing about "binders full of women" was a classic Romney statement. It involved office equipment, which is one of Romney's life passions (if you doubt me, consider Romney's strangely hands-on involvement in the creation of Staples, which was less CEO-like and more cheerleaderish). It gave an air of preparation, which Romney loves to evoke. He's always talking about being ready on day one, and his office equipment fetish probably springs from this appearance of being prepared: What says you're prepared like a bunch of sharpened pencils, a neat binder full of facts, and unopened packages of pens? The statement was also representative of Romney's passions because it was a lie. And it indicated a greater problem with the way Romney thinks of people—as commodities in a portfolio, ready to be exploited.
The fact that Romney believes one of the major concerns of women is being home to cook dinner was more damning than the binders comment, but the binder comment was an evocative image that set itself up for a number of quick, easy jokes. That said, it's time to move on to the meat of what Romney said, rather than some awkward phrasing.