I applied to schools last year, and didn't get in. I applied again this year.
I don't know about your discipline, but in psychology, it's not all that uncommon not to get in the first application cycle just because all of the programs are SO selective. There's actually a poll and forum topic ("Shutout Count") on it in the Psychology Forum section. Last year I applied, not realizing this; as the application season wore on and I learned about my peers on GC, I realized that it was naïve to assume I'd get in because I was a strong candidate with great test scores and great grades (and a masters degree).
So as long as you're actually doing something and then reapplying, you've always got a shot, but if you weren't going to change anything (test scores, work experience, research experience), there probably wouldn't be much point.
Mine is a strictly psychology perspective, and I haven't actually gotten in this second time, but I hope this second time is a charm for us both.