According to one of my college professors, men tend to fall in love right away and women have to get to know a guy first before they fall in love with him.
I think it is very common to feel some kind of connection with another person the first time you meet him or her, but I would characterize this feeling as more likely infatuation and/or physical attraction than real love.
There was a guy once who told me that he fell in love with me at first sight, and he was so sweet and so romantic on our first date that by the end of the evening, I was thoroughly smitten with him as well. However, we were both young teens at the time, and emotions tend to be so very intense at that age. ;)