We've been calling ours "Nibbler" in reference to the Futurama character who can eat anything and everything because I was literally hungry ALL THE TIME the first 2 weeks or so after we found out. :)
I can't explain why, but I didn't like calling the baby "It" either. It felt too impersonal. Somehow, giving it a temporary name makes me feel more bonded to it? Maybe I'm weird, but I like having a name for it. :)