I don't know about you, but I just love it when certain enemies you face - especially ones that you face often - has one 'good guy' who helps you out or even joins your party. For instance, Goris in Fallout 2 is a deathclaw but is able to speak and is somewhat intelligent. He even joins your team and fights for you. I just find that to be a novel idea when done right.
Fire Emblem does it a lot, too, technically. Some enemies can be spoken to (though there's rarely any indication that they can, and even then, you have to talk to them with the right unit. This can piss me off sometimes when playing blind. Looking at you, Arya)
If you happen to know of any instances of this from other games, throw 'em out now. I like seeing this in video games.