check out the top forums on the site...these are some of the people you are competing against...It's getting more and more competitive every year. But it's pretty much relative to each applicant..
As stated above, check out the sticky titled: GPAS,GRES, XTRAS to compare yourself to other applicants. It gives you a good idea of where you stand at a statistics standpoint, but your personal statement, LOR's, and interview are very important as well. Goodluck.
It also depends on which part of the country you want to attend. The number of schools out east dramatically out number the schools out west, so it goes to say, it is much more difficult to get a spot on the west coast versus the east.