I just read a very good post on prostitution. It demonstrates that all arguments against legalizing prostitution are either religious or paternalistic in nature and thus should not be taken into consideration. It's hard to disagree with such a logical and well-presented argument.
Still, the idea of legalizing prostitution makes me feel uneasy. If, as this post argues, prostitution could always remain as "merely the exchange of money for sex between two willing individuals" there would be no problem. This is, however, often not the case. Many women are trapped into prostitution by pimps and find it next to impossible to leave the industry when they want. While prostitution is still a crime, they can at least have the hope of denouncing their pimps to the authorities in order to free themselves from exploitation.
Another problem is that I don't see how it will be possible to untie prostitution and drug business in order to legalize the one while considering the other criminal.