I can speak for my experience. Last application cycle (2005-6), I applied very late (a week before the AMCAS deadline). I was interviewed at two places and after getting on those waitlists, I decided to reapply the next year (2006-7).
My re-application was the same in substance (same MCAT, same GPA, same ECs, and only one new LOR--I even used my same PS), but I rewrote a lot of my little AMCAS activity blurbs, proofread my application better, and applied hella-early. Of the schools I applied the second time around, six were reapplications and fourteen were new. I got a total of ten interviews (one from a school I applied at the year before but did not interview me).
At every interview I was asked if I had applied the year before and why I thought I did not get accepted. I was honest and I've gotten three acceptances and a couple waitlists so far.
So reapplying is not the kiss of death. I think so much depends on where you apply. Think about it: I applied to 20 schools this year and only ten interviewed me. If I had only applied to those ten schools that I have not had an interview at, I would be saying that reapplication is impossible. And if I had only applied to the ten schools where I got interviews, I would be thinking that my application is God's gift.
Maybe in your first application cycle you just pick the wrong schools (i.e. your background just doesn't resonate with that school's administration), or maybe you submitted your application too late, had some spelling errors, wrote a crappy PS, had only so-so letters. Any of those things could affect your application significantly if you didn't go to Harvard, pull down a 35+, and finish undergrad with a 3.98.
But if you do reapply, you might as well try to spruce up your application in the meantime. It can't hurt to be overqualified for medical school.
For what it's worth.