I posted about this regarding myelf in the NF forum as well as some in my introduction post and probbaly a few other threads too...
At the moment, I'm strongly leaning toward being INFp, but at times question both F/T and J/P possibilities. I made my decision to decalre myself INFx based on seeing the NF temeperament as a pretty clear match as far as my values and motivations go compared to NT values and motivations.
I could be...
INFP with a well developed Ti and somewhat developed Te. Bluewing recently posted an INFP profile in the NF forum and I found I agreed with most of the part about how dominant Fi and Ne interact but only a little of the part on Si and virtualy none of the description for how Te should show up in an INFP agreed with how I see myself, but I do exhibit some of the negative traits of Te in the inferior function role as written about in "Was That Really Me" by Naomi L. Quenk.
INTP with a well developed Fi and values of an NF. Oddly, while this option seems to make the most sense to me, it goes directly against commonly accepted type theory in that an NT would not value the same things to the same degree as an NF (values, feelings, importance of relationships, need to apply personal sense of meaning to nearly everything). I believe I think like an INTP (when I read a post here and find myself saying "that sounds a lot like me" its nearly always an INTP), but I don't have the same value of logic and don't look at the pursuit of knowledge the same as they do.
A confused INFJ. A few posts in my thread in the NF forums do point out cases where I use and may even prefer Fe. If Fi can cause Fe to introvert its use for an INFP, then maybe Ni would have a similar effect on Fe, but I still think Fi makes a better case for being my dominant function than Ni.
A confused and poorly developed INTJ
I suppose its even possible I could be an ENFP but I really havnt given that much thought to that option. I consider myself highly introverted (less so on-line, but very noticable off-line), but I do feel a frequent need/desire to act on my ideas which dominant Ne fueled by a strong Fi might reflect.
Oh, and FWIW, I was born on the cusp of two different astrological signs, but thats just a tangent to the thread title IMO.