I applied to 14 schools
3 ivy leagues that I knew I had little chance of getting in to (but figured, what the hell)
The others were Univ of Iowa, St. Louis Univ, Univ of Kansas, Univ of MO-St. Louis, Bowling Green State (in Ohio), Univ of New Mexico, SUNY-Albany, Univ of Kentucky-Lexington, Wash U (in St. Louis), Univ of Montana, and Arizona State.
I interviewed at 6 schools, still wait-listed at 2, and got offers from 2.
In retrospect, because I'm aiming for an (eventual) academic position at a university psych dept, I now wish I would have applied only to really top-notch programs (and more of them. Some of the programs I applied to do fall under this category in my mind, but some do not.) After getting a great deal of the way through the process by basing my search primarily on fit (which is an approach most here will advocate), I was told by several professors and recently read in several books that, if I want to get into the competitive world of academia, I needed to go to the best program I could get into, regardless of fit. PERIOD. My final choice (Univ of Kansas) reflected a compromise between these two foci.
So, apply to as many schools as you can comfortably afford and make sure that your choice of places reflects not only your interests, but are also conducive to your goals. Good luck!!