No kids.
No pets.
King. I spread out so much here's barely room for us.
Queen. No kids (occasionally they climb in bed with us but it's not an every night thing) and we don't allow pets in our bed at all.
Queen....with room to spare.
King. My mans 6'3" His feet would hang off the bottom in any less.
Queen, but we're both over 6'2 so we're upgrading to a king :)