Well, It's pretty much obvious what I would vote for!
Considering Yoda has a spot on my Signature, Chihuahuas are my choice. He happened to me...Yoda's a rescue, and they best little dog in the world.
Who knew something so little could be as good a watchdog as any of ny prior big dogs? He was over 2, closer to 3 when I got him, abandoned and scared. He's my pal.