i am an active member of POF and i
love love love it
everything is totally free, but you have so many options and filters available
like you can set it so only men of a certain age or relationship status can contact you. there are also good questions in the profile setup, like if you smoke or drink. plus they give you a lot of options for the "seeking" category (hang out, long-term, talk/e-mail etc...)
i also like that you can embed music and post links to your other accounts, like your yahoo or myspace (i know some paid sites that don't even let you do this!). you can also IM for free
(with webcam, if you please) and you can even make an anonymous phone call to another user.
there's also forums (quite entertaining indeed!
) and the moderator actually addresses issues that the members have.
as you can see, i am a huge fan
i love online dating...so much fun!