If any other state legalizes prostitution, it'd most likely be more along the lines of high end escort services (which are not only already de facto legal but also regulated in many major cities) rather than brothels.
As for which state would be most likely to do this, eh, Colorado.
There are too many interests against legalizing prostitution for it to happen any time soon.
Okay, I'll bite. Other than the SoCon vote (which in this case would extend easily into most of the soccer mom demographic), what interests do you speak of?
Besides SoCons, I would say there's a feminist stance against it, though there are pro-prostitution feminists. Your general NIMBYs, who are not necessarily SoCons, may object for a variety of concerns, whether it be land value, sex tourism, setting examples for our kids, and whatnot. Some bleeding hearts might find it exploitative of the poor. Business interests in Nevada could try to fight it outside the state as a deterrent for Nevada tourism. Police unions would probably fight it.
Some good points, but in all fairness, most of those would also apply to those opposing legalizing marijuana as well.