Yes, prostitution should be legalized.
The only victims of prostitution are the prostitutes themselves. They are beaten raped and robbed, yet they are unable to ask for protection from the police. the reason that there is so much drug use and violence is because we as a society has pushed it underground.
The percentage of prostitutes with STD's is actually lower, more like 20%, with teenagers closer to 40%. In Nevada, where it's legal in some places, the women are required to be tested regularly. It is a competitive business, and each business wants to provide the best service. Why would they not want to provide the best service?
Plus, women (or men as the case may be) would not be working for pimps but for themselves in a clean environment with bouncers and panic buttons for their protection. If it's licensed like most service industries, this would lessen underage workers. Plus, the government would be able to tax and use the police currently working with vice on something more helpful to society, like murders and child molesters.
As long as it is between two consenting adults, why should it be illegal?