Yikes..I'm in the minority here. I say no for several reasons including the fact that if you need to pay for sex, you don't deserve to get it. Now...if she hunts you down and ***** you for your money...that's different. You didn't go out looking.
Other reasons...infidelity is dishonesty...that's the one thing I can't tolerate in a relationship. Now...if you're not in a relationship then refer to aforementioned reasoning. And, yes folks, STDs...
So...while it'd be interesting to have it legalized (tax increases, regulation) and I am whole heartedly against *more government* and telling people what to do, I'm not going to push for legalizing it because it doesn't affect me and is against most (but not all) of the moral fibers in my body.