Do opposite attract?

I've watched the movie "You've got mail" for like, the hundred time.. :P and I did it again tonite..

In Nora's commentary, she said
"... If you ask people who is the perfect person for them... they will write down democrate, play tennis, etc. So they basically wrote down the description of themselves. They want to meet themselves ... "

Is this true? So I asked myself an aged old question of "Do opposite attract?"