A routine porn movie or a conventional-looking porn performer. The range of dirty movies I can rent at my local video shop is about as broad, compared to the range of possible sexually-explicit entertainment, as the range of muffins is compared to the range of all possible food. The world contains a huge range of sexy sorts of people and sexy sorts of sex, and yet the representation in porn has gone from painfully narrow to even narrower.
One of the reasons I find the muffin analogy useful is that it's a way of talking about the depressing narrowness of the genre as it currently exists without necessarily condemning the material itself or the people who enjoy it. You can like muffins just fine without wanting to subsist on a diet of nothing else for the rest of your life.
Procrustes, in Greek mythology, was a bandit who stretched his victims or cut off their feet so they would exactly fit his bed. There are two kinds of sexual Procrusteans. One finds that his sexuality is not in tune with his ideology, and tries, through force of will and self-reproach, to reshape himself to fit. The other kind devises an ideology that proves that his own peculiar sexuality is actually the correct one that everyone else should adopt as well.
The notion that anyone has one sexual type, one ideal lover, does not match my experience of reality. The Archipelago is a name for the complex set of nodes of attraction that I think each of us has in our libidos. Labels, particularly for sexually orientation, can provide the illusion of order and obscure the complex outlines of these shapes, blurring out the fractally complex boundaries of what we actually find attractive.
Discussions of many topics, particularly on the net, can be drawn towards well-worn paths of rote agreement or reflexive opposition. This tendency often obscures fresher or more subtle approaches to the the subject, or consideration of related but distinct subjects. I call these more comfortable and familiar arguments gravity wells.