Hm, Waterclone might want to take a class in statistics and probability, and people might want to read the Wikipedia article more closely to figure out what terms actually mean. For starters, "Receptive penile-vaginal intercourse" refers to the act of a woman receiving a penis in her vagina, so that statistic is the WOMAN's risk of contracting HIV from an infected man. The risk for a man who has sex with an infected woman is listed under "insertive penile-vaginal intercourse" and is estimated at 5 infections per 10,000 exposures, not 10. In other words, the risk of infection for a woman who has sex with an infected man is twice the risk for a man who has sex with an infected woman. (This makes sense when you think about it. The woman's vagina is the receptacle into which most of the fluids are deposited.)
Also, the risk that Waterclone mentions of 1/10,000 from "fellating a man" is the risk which a woman experiences when she gives a blowjob to an infected man. The risk which a man experiences when he GETS a blowjob from an infected woman is listed separately under "man being felated." Once again, the risk of that sex act to a man is only half as high as the risk to the woman: 0.5/10,000.
These numbers make the risks sound low, and they are low for an individual sex act. The thing to bear in mind, however, is that people don't just have sex once. The number of people you have sex with, and the frequency with which you have sex, can amplify a small risk into a significantly larger one. The way this works out is that there is higher risk for women who work as sex providers than for men who visit sex providers, and of course the risks are very very low for people who are monogamous.
You also have to take into account the percentage of the population that is infected with HIV. The U.S. Centers for Disease Control estimates that currently about 1 million Americans are infected -- roughly 1 percent of the population. However, the risk is not uniformly distributed. Men who have sex with other men account for nearly half of all people infected in the U.S. (even though gay and bisexual men only account for 4% of the U.S. population). Women account for about 1/4 of all HIV infections, so the likelihood of an individual woman having HIV is about 1 in 600. Obviously the risks are higher for women who sell sex for a living or who engage in other risky activities such as intravenous drug use. I'm not going to bother trying to carefully estimate the breakout of those risks, but I think it's safe to guesstimate that the likelihood of a woman being infected is less than 1/1,000 if she does not fall into one of those higher-risk categories.
On this basis, we can see that the risk for a man who only has sex with his wife is quite low. Even if he doesn't know everything about her past and current sex life, he can reasonably assume that there is a less than 1/1,000 chance that she is infected. Let's assume that they have an enthusiastic sex life and fuck three times a day. That works out to roughly 1,000 acts of intercourse per year, so his risk of contracting HIV during a year of fucking her is 1,000 time the risk of her being infected (1/1,000) times the transmission rate per instance of vaginal intercourse (5/10,000). His annual risk of infection is therefore 5/10,000. Even if they have sex at that rate for 50 years, he only has a 2.5% chance of getting HIV.
Now consider the case of a woman who works as an escort and has bareback sex with 5 different men per day. It's reasonable to assume that the risk of each of those men being infected is higher than the general population, so let's estimate that 1 in 50 of her clients has HIV. Her risk for infection during a single act of intercourse is still quite low (1/50 X 10/10,000 = 1/50,000). Over the course of a year, however, she has sex about 1,500 times, so her actual risk of contracting HIV is about 4% per year, which means that in 10 years of working as an escort, she would face a pretty substantial risk of getting the disease.
The risks would be higher for streetwalkers than they would be for women who work at an incall service, partly because streetwalkers' clients are more likely to be infected and partly because streetwalkers have less opportunity to inspect their clients and engage in other safe sex practices. The bottom line, though is that condom use is a pretty important safety measure for women who sell sex. If I were a woman in this business, I would absolutely insist on condoms. Men, on the other hand, would probably be pretty safe even if they had unprotected sex once in awhile, so long as they didn't make a regular habit of it. But still, I wouldn't do it personally. On top of HIV risk, there are some other STDs that I'd just as soon not experience.