Human-animal genetic hybrids, no Beasty.

We evolved from monkeys, why would we want to go back?

Ever read The Amazing Spiderman? In many cases, they used animals as a way "regenerate body parts", the most well know being The Lizard. It's both helpful, but also it can make us look awfully neat.

I suspect it would be difficult to modify specific body parts, since an animal, as a collective, is a system that is designed to function with itself. You would have to do some pretty hefty engineering most likely, and at that point, why not just create something completely new?

Because that would put us in the War Zone, soon enough. The new creations would figure they were better, and rebel. On the other hand, their would be some crazy side-effects from the altered humans, so the same thing might happen.
I just like it for the idea that we could, more or less, make ourselves look however we want. Maximum customization!