A high score. Seriously though, I don't think any "magic" numbers exist, but I would probably shoot to be at least 1 standard deviation above the mean.
If you're looking for places like Brigham and Women's its pretty high. I know someone with 230 on Step I and Honors throughout third year that didn't get an interview there. But for all but the top 10 programs, its probably safe if you have over 220 on step one.
