On the one hand, there has to be some kind of physical attraction. I think that sex sort of requires it.
Nobody should feel bad about that.
On the other hand, although I know the difference between Plain Jane and Luscious Lola, other factors - her smile, personality, wit or the way she makes me feel about myself - might mean I play with Jane and not Lola. My tastes are pretty broad. Let's say that I find about 50% of women in a given room physically attractive.
We haven't been at this long enough to say whether our 'pickyness' will change, but I can see how that could happen when the excitement of the novelty has worn off.
-B