My mother is a career counselor and a big fan of the Myers-Briggs test. She's typed all of us in the family.
I am an ENFP -- sometimes an INFP depending on my mood the day I took the test. I am very strongly a Perceiver rather than a Judger: a great improviser but not good at planning ahead, willing to be fluid about making plans. Which is helpful if somebody you know has opera tickets they can't use at the last minute, but definitely unhelpful for all those things that require advanced planning -- you know, paying bills on time...
I am also pretty strongly an iNtuiter rather than a Senser.
I've definitely shifted on the I-to-E spectrum over the years to much more extroverted. Part of this is circumstances; now that I'm unemployed (er, ah, "consulting") and spending a lot of time at home, I really feel the need for human contact.
When I worked at a tech startup in S.F., the "human capital development" department had everybody take the Myers-Briggs. Unsurprisingly for this inbred little ivory-tower company full of Ph.D. linguists, attorneys, and software engineers (I was the least educated person there), nearly everyone was an INTJ or INTP.