I don't believe there just one preference. A certain wealthy man who published a well-known magazine preferred biker types openly but I do know that the cheapskate hired male prostitutes who were anything but butch. His main preference tended to be large penises, which seems to be a prerequisite for many gay men.
A well-known New York lawyer/politician liked young Latino men, even if they were underage and other wealthy gays preferred men who looked like them, but that seems to be a preference of the lower classes as well.
A friend of mine, who knows every gay man worth knowing, once told me that the richer they are, the sicker they become in their sexual practice. His observation only makes sense, since a person with money has the wherewithal to buy his fantasies. I would imagine the same applies to a lot of straights as well, if Tiger Woods is any indication.