There was a girl at Auburn who wanted a certain sorority and nothing else. Very often this turns out badly but the third time she went through formal rush, she got a bid from them! In the meantime, she had made sure that her gradepoint was high and her activities looked good. The weird thing was that her sister rushed a couple of years later, pledged that group, and depledged within a month.
I rushed twice. The first time I didn't like my results, was taken up with cheerleading, and knew I'd be transferring at the end of the year anyway so I dropped out. I was worried about my chances because I was a junior transfer (back then my first school didn't allow you to rush until sophomore year), but everything tuned out fine. The main thing is, you have to make yourself really look good the second time around so they'll see what a jewel they missed out on the year before! And make sure you get to know women in every group, too.