e-Harmony - You've seen their ads on TV and heard them on radio. Take their Personality Profile and get instant, objective feedback on yourself and how you relate to others.

Friendfinder - With over 1,000,000 registered users, this site always has thousands of personal listings - plus chat rooms, articles and advice for Singles.

Match.com - Now offering advice from Dr. Phil - A diverse, global community of quality single adults who share common goals - intelligent individuals who want to find great dates, make new friends, form romantic relationships or meet life partners.

Great Expectations - As a member, you get access to a team of relationship professionals and thousands of member profiles. Also, you will receive invitations to Great Expectations parties and events exclusive to members.

Metrodate.com - Search member profiles with personal messages, photos, videos, and voice messages from singles that are anxious to meet you. Sign up for a free membership to create your own profile, visit the chat rooms, message boards, dating tips and more.

Chemistry.com - This site is designed especially for people who are actively seeking meaningful, long-term relationships, with the belief that meaningful relationships are built on two equally important foundations: compatibility and chemistry. Other sites may help you find out if you're compatible, but Chemistry's system is designed to help you find both of these essential elements.

Date.com - They currently have over 2 million members worldwide and are signing up approximately 50,000 new members a week. Members can browse the site, post a profile, and include a photograph for free. When the member’s search identifies someone he or she would like to contact, they can upgrade to a Gold membership and send email, instant message and chat online.

AmericanSingles.com - They are one of the largest online dating communities in the world, with millions of profiles and pictures.

PerfectMatch.com - In addition to lots of profiles and pictures, they offer a free Compatibility Profile... plus advice from relationship expert Dr. Pepper Schwartz.

Yahoo! Personals - Since people have different dating priorities, Yahoo! Personals offers two different services. One is for fun-seeking casual daters. The other is for people searching for a lasting relationship. So, which one are you?

2 of a Kind - They have the Net's most powerful match system featuring 150 matchable traits and interests, match analysis, anonymous email, free registration.

Sugardaddie.com - Consider looking for love among the "Beautiful People." This site claims a member base that contains "millionaires, models and professional businessmen and women who welcome a quality approach to modern online dating."

ChristianCafe.com - A cozy, comfortable virtual Christian Dating Service designed to enable single Christians to connect with one another in a virtual Cafe setting, from pen-pals to potential relationships.

Jewish Mingle - A singles online community dedicated to helping men and women meet other singles in a comfortable online environment offering chat rooms, message boards, photo personals, a photo gallery, anonymous private mailboxes, and more.

Jewish FriendFinder - You can meet singles within the Jewish faith. Search over 90,000 Members worldwide. Anonymous email, chat, and Instant Message.

Here are some great sites for Mature Singles:

Prime Singles   - Meet an older woman or man today.  Instant messaging, message boards, and chat rooms for older singles. Enjoy this comfortable community for mature singles.

SilverSingles.com - Operated by American Singles, this site lets you connect with singles near you for dating, romance and friendship, using photo personals, email, chat, IM and more…

Senior Friendfinder - Meet Active, Single Seniors for Friendship and More. The most popular place for people over 40 looking for romance, dating and friendship.

Senior Singles at Date.com - "A relationship community committed to helping its members find and maintain the best relationship for them."

SeniorMatch.com - They claim to be "the world's best place for meeting people over 50 for love, friendship and more." This site offers a place for 50-plus to interact with each other, talk about religion, sports, life, relationships, and more.

And here's a couple of sites for those NOT exactly looking for a committed relationship:

Ashley Madison Agency - ahem, how can we put it... Ashley Madison caters to men and women who may be in an unfulfilled relationship and are looking for extra marital or open spousal relationships.

Passion.com - They offer sexy personals for passionate people tired of playing the dating game.