That being said the one non-human companion I would love to have is a halfling MALE, because if we had to suffer through all those gnome companions in D&D games I think we finally deserve a properly written halfling. Just don't make him into a goofball, like a barbarian who carries a gigantic weapon on his small frame.
I enjoyed Tommi Undergallows as a halfling rogue companion in Neverwinter Nights, and I never thought it was a badly written companion.