OK. When I do the Meyer/Briggs thing, my result usually depends on where I am when I'm taking it. If I'm at work, or some other professional environment, I come up ISTJ:
Harry Potter Personality Quiz by
Pirate Monkeys Inc. If I'm at home, or some other social environment, I come up INTP:
Harry Potter Personality Quiz by
Pirate Monkeys Inc. I think they're both spot on. But what a dichotomy of characters!