Dating

1) Match.com - Most popular, but a lot more men than women.
“Match.com, the leading online dating resource for singles. Search through thousands of personals and photos. Go ahead, it’s FREE to look!” - Match.com

2) Yahoo! Personals - Best price of the top five.
“Discover great singles near you. Search personals with pictures and post your own free profile to make a connection. Find your perfect match.” - Yahoo! Personals.

3) eHarmony - More women than men. Lots of marriages from successful matches.
“Personality matching of couples on 29 dimensions that determine long-term success” - eHarmony.

4) Perfect Match - Becoming a better service every year. Seen in several movies.
“Perfectmatch.com is an online relationships and dating community featuring singles serious about finding love and lasting relationships.” - Perfect Match.

5) Chemistry.com - Focused on relationships. A lot like eHarmony.
“Chemistry is an online dating site, based on revolutionary science, for singles who are actively seeking a long-term relationship” - Chemistry.