My polar opposite is definitely ISTJ according to the eight function model:
INFJ: Ni, Fe, Ti, Se, Ne, Fi, Te, Si
ISTJ: Si, Te, Fi, Ne, Se, Fe, Fe, Ni
There is a world of difference between "enlightened" ISTJs (I have a few good friends, of this type: witty, loyal, knowledgable and quirky people, in general) and unevolved ISTJs (rigid, pedantic, critical, idosyncratic and controlling).
My manager in my old Lab in the UK was of the latter type - to make matters worse, he was severely stressed and beginning to unravel at the seams. We went from a good working relationship to continually clashing as he spiralled out of control.