The best type of tail

Recently I've been wondering, what is the best kind of tail? I can see a monkey's tail being quite useful, after all it's basically an extra limb. Grabbing the milk, climbing a tree, holding a pencil, things like that. It would be a huge advantage in just about any situation, it also would have benefits to your balance. At the same time though I would like a scorpion's tail. Not only would it look awesome but imagine how sweet it would be for a fight. Some guy pulls a knife, you slowly and dramatically raise a massive scorpion tail over your head. The guy takes one look at it and runs away. It's kind of hard too decide, even like a lizard tail would be pretty cool. Leave a comment about what would be the best kind of tail. I'd like to hear your ideas.