I think you are most definitely an ISTJ. The way you consider things screams that to me. I don't really see the extroversion so I wouldn't consider ESTJ. The F thing to me isn't indicative of anything other than being somewhat unsure of yourself and how you influence and interact with other people. More of a personal quest type thing.
My cold, snide, intellectual life is just a veneer, behind which lies the plywood of loneliness.
You definitely seem ISTJ especially with the things that you were saying in the " Which Type has the Richest Inner Life?" thread. You seem very detail-oriented and methodical when you were talking about the World of Warcraft.
But people think I'm warm and cuddly. Some other people think I'm too abrasive toward other people which suggests INTJ.
You totally remind me of my brother who I'm convinced is ISTJ. Guess who is more "warm and cuddly": the INFJ or ISTJ? The ISTJ by a long shot! He would be the one person that would give everyone hugs. However, if you talk to him, he is very structured lives by his own set of rules and values tradition a lot. Being "warm and cuddly" does not have much bearing if you are "F" or "T". So you can still be a friendly ISTJ.