Applied to 35 schools with 10 interviews invites and 6 acceptances so far. Non-URM, MCAT > 34, non-trad, and somewhat unique EC's with fairly strong medical background.
Contrast that with last year where I applied to 15 schools with 2 II's and no acceptances.
In hindsight it would seem that applying to that many schools this year wasn't absolutely necessary, but it was interesting that some of the schools that I thought were long-shots gave me interviews while many of the low-tiered schools I thought I had a good chance with gave me silence. And several of my acceptances are ones I added later on my list.
From what I've observed in the past couple years (though my data is admittedly limited), it seems that if you have fairly balanced numbers with standard EC's and background (or have schools available with strong in-state preference), it's probably safe to just go off the MSAR and apply to a reasonable number of schools in your GPA and MCAT range (say 10-15) with a couple below and above your range to cover your bases (i.e. your dream and safety schools). If your numbers are skewed, though, (e.g. low GPA and high MCAT) and/or have unique EC's, URM, non-trad, etc... then it's better to add more schools to your list. There seems to be some unpredictability in how the schools review non-standard applications. Just my 2 cents...
To add one other data point, I have a friend with similar stats as mine (though more research heavy and less medical experience) who applied to about as many schools as I did the first time and had the same results (0 acceptances). He only applied to one state school the next year, though, and got in.
