The problem with using any of these kinds of pieces as your tag line is that others are probably thinking the same thing.
Peruse a couple of dating sites and you'll quickly see what I mean: "I'm the one your mother warned you about," is still a favorite after more than a decade of use, and many online daters steer clear of anyone using this tag line because of it. Try for thought-provoking, unusual and/or intriguing one-liners.
They differ in that they can be easily changed and provide a bit more space to describe whatever it is you feel relevant.
Quotes from famous people that you admire, agree with or want to emulate are quite popular in tag lines, as are truisms and lines from famous movies or songs.
"A handle (or user name) is the name other members of the dating site will use as your "name".