I've actually given this far too much thought, which means the universe will instead gift me with someone completely different.
My one main requirement is that the guy be a T. I am F enough for two people and I don't need another F cheering me on to being more emotional. I like the calmness of a T as they naturally make me calmer through sheer empathic osmosisness.
Ideally, overall I would say an XNTJ. The easiest instinct stacking would be some combination of SX and SP as that is what I am, but they seem to be rare as I always meet heavy SP-dom, sans SX INTJs. And I rarely meet ENTJs. What I appreciate the most is that xNTJs are especially gifted in focus, insights, and problem solving from perspectives that I don't normally consider. There is also an incredibly depth and richness to the loyalty that I have had from these types that is flavored differently than what I have experienced with other types. I think this is due to how selective, INTJs especially, these types can be when considering who is worth their time and energy.
xSTPs: Not a bad fit either. I find them to be my true opposites in many ways, but because of this they can complement my weaknesses quite well. Some challenge in getting an ESTP to shut up and an ISTP to speak up, as well.
XNTPs: These guys are addicting at first but eventually I find the Ne-Ne-ness to become a sticking point. We both want to be funny in the same ways, or we both want to idea generate into nothingness forever... and nothing really gets accomplished. ENTPs are quite awesome though...
xSTJs: Girl STJs seem to love my Ne-bouncy castle, but the guys I know are never particularly impressed or amused.