--------------------------------------------------------
I agree with mnealtx. But I don't believe so much in the seemingly mystical connotation of "there's just one person that perfectly right for you in all of the world". I think that there are many people that are very, very compatible for you but you have to be very patient to find one of those.
When you do, and they become your best friend for life, then I think you've found your soul mate. I think people are in too big of a hurry to find that someone (if not just anyone) and end up spending years trying to make things work out with somebody that they're just not compatible with.