First post here and I am in the midst of a slow career change... to what I am not particularly sure as of yet.
So first of all, I will address the whole Engineer/IT/Math stigma...
Not sure why that it is so widespread, while sure INTP might be able to do it quite easily, the reality of the world dealing specifically with the job roles, might push the INTP to pure boredom. Such is the case with myself.
1) The actual job in IT is often delegated to you, and you are generally working on uninteresting problems. Being a Computer Scientist in the field of Robotics/Artificial Intelligence or something similar in a university setting might prove differently, but alas, my love affair with programming died long ago. I started writing Lisp along with Basic when I was a toddler.
2) I have a general disdain against modern corporations, where, most of the applied skills to mathematics/computer science/engineering would be used. So... I generally do not see the purpose or big picture behind being a cog in somebody elses machine, it is actually quite degrading.
OK, so back to ME...just kidding, I have learned to kill my ego at will...
I am going back to school in pursuit of a degree in Political Science... though I am not sure I am set on a career as a professor.
I chose this based on careful observations on what I might be able to do with it upon finishing, which would be being an adjunct as well as consultant/social scientist. I could also still do journalism and use my former computer skills in this occupation, or shall I say, possibilities of occupations as the end "occupation" I have found does not exist for the INTP, at least myself...there is always something else, or a bigger project.
I am still skeptical at this at the thought of living in any one place for too long as I have a preference for change. Though knowing I might not be able to predict my future self at 40, 50, 60, 70, it seems like an OK degree, at least to qualify my actual intellect amongst business peers who I have felt were of inferior intellect for years.
I will tell you other careers I have thought about, but doing the proper investigating turned me off. Law, but the general investment as well as personality types I would run into, I was already getting away from. The only real thing that I like about the Law is specific areas like natural law/jurisprudence, which would be better suited to a career as a professional philosopher than a lawyer.
I have considered journalism, but the reality of being a "journalist" and working for some hack in a news room...not too fun, plus if you look at the trending towards "new media" and out with the old, there are already quite a few journalists. Also, it is a relatively low paid career.... So I have delegated myself to covering more intellectual aspects of journalism on the side, such as on a blog, expert pieces or other such interests.
I think being a writer would also work well for the INTP, especially ones who can use their (f) shadow to go into the human side of characters. Again though, the actual life of a writer, much like the journalist, might delegate this to a hobby.
So basically, in the modern world I need something with flexibility, changing projects, and intellectual rigor, hopefully these will be provided under some research/adjunct faculty. I will leave my "hobbies" as hobbies, but there is no reason you can not make moneys from "hobbies".
As far as computers/IT goes... I once amassed a network in my house, which was definitely more powerful than many companies. I eventually sold some of this to a bank which wanted to setup crisis backup systems. My SO pushed me to get rid of this. I basically had a few 42u rack servers in my house, along with other various crap I had collected.
Also as an INTP I used to be quite the "collector" of books, cds, mp3s, you name it... I had around 6 terabytes of data from newsgroups/ftps of various video/albums ... I gave it all away though, as maintaining the collection took up too much of my time, this was almost 10 years ago so that amount of data was extremely impressive back then. I tend to only collect smaller, and extremely obscure novelty items now... Otherwise I would have stuff stacked to the ceiling! If I eventually purchase a house, and know I am not going to move again.... then I could see it getting back to that state.
If time was limitless, I would definitely pursue the life of the polymath, and get multiple PhD's across several different fields. To me that is the burden of other INTP's I have talked to...the limits imposed on them don't respond well to the infinite possibilities of the mind.
Anywho...Yeah career decisions are rather tough.
