Well in all honesty, I only know three other ISTP's, and the ones I've met on this forum. But the ones I've met in person I've classified into two groups that I've designated an animal to help illustrate my point:
The bears - the quiet, gentle giants (assuming a bear is gentle). They might play football, or soccer, or any typical sport, and be satisfied at that. They also do better in school than the others. Very easy going, seek a leisurely life. Avoid dealing with conflict.
The panthers - Sleek, silent, deadly, heroic, cold appearance, terribly turned off by school, into leisurely yet risky sports. Risk takers, actively seek an exciting life. Put more forethought into their actions. Goofy, takes nothing seriously, most outgoing of ISTP's, holds the greatest lack of caring for what the public thinks of them.
What are your thoughts?
Edit: I think I'm going to combine the last two, because I feel I fit into both of those as well.