I prefer to use the word "partner" instead of the abbreviation "SO"

I don't like partner because it sounds like either a business partner or someone being overly warm and fuzzy.

that's a strange pair of problems! both too impersonal and too personal.

Exactly! For me SO (s.o.) sums it up. It's a bit hokey sounding, but it covers a lot of bases and seems "just right" in terms of personal-ness.

I think both sound almost comically "hip" and dislike either term. I might hate one marginally less. But that don't mean I like it.