also, *definitely* apply to your state school(s). that is where you often stand the best chance of acceptance, because the simple fact that you call yourself a resident of that state works greatly in your favor. also, many private schools slightly favor residents of their state, although not the same extent as state schools.
other than that, i echo everyone's advice that you need to apply to a broad range of schools. it's impossible to predict where you're competitive at, so don't shoot yourself in the foot by limiting yourself *only* to highly-ranked schools. but at the same time, definitely apply to a few dream schools where you think you stand no chance--you may be pleasantly surprised. how many schools you apply to depends on 1) where you live, 2) how competitive your GPA/MCAT scores are, and 3) how much money you're willing to spend. i applied to 23 schools, which is on the high side, but this is my second time applying to med school (i only applied to about 5 schools the first time) so i went for all the marbles.
hope this helps.