I had to jump into this one...
There is no question that I believe it should be legal. In fact, in certain counties in Nevada, it already is legal. Let me try to deal with the arguments...
1- The government should not exercise dominion or control over a person's body. This goes for all examples...prostitution, organ sale/purchase, seatbelt laws, abortion, eating trans fats etc. Completely ridiculous that any one group can tell another what to do with their personal bodies. Ask yourself this question...if you were diagnosed with kidney failure, and had the means, would you not post an ad on craigslist offering to buy a compatible kidney for $25k? You bet your a$$ I would. Fact is, its illegal. You are just trying to survive...well so is the 22 year old who turns tricks.
2- Legalizing prostitution would remove much of the "street element" from it. You would provide a safe place in a regulated agency to perform the trick. A prostitute would not be beholden to pimps or other street level figures. Also, safe sex practices would be mandatory...if the john doesn't cooperate, no sex and onto the next client. The environment would be far safer and violence against women would plummet.
3- Allocation of resources. Let the vice cops spend their time where it is warranted, not busting prostitutes (trying to get to their pimps). Furthermore, the operation would raise revenue for the municipality where it is located through the normal payment of taxes.
4- I'm quite certain that most would not want their wives/daughters as "working girls," but for some it may be a viable way to earn an existence while working towards better thing. Most people would want the young hottie as a prostitute, not someone older. Hence the high turnover that might be expected.
5- Anyone who says most women are repulsed by it...please ask some women you know. Lay out different scenarios for them, their responses may suprise you.
6- Legalized prostitution is already practiced in many developed countires of the world and in certain US counties. The world as we know it has not ended. We are not exactly breaking new ground here. Studying those areas would help transition any problems that arise from legalization.