No no, that title goes to Mosquitoes.
I wouldn't be so hard on humans. We're an extremely complex, but also infant species, with a lot of unique traits which make us distinct. Nature itself doesn't impose moral precepts of good and bad, and so its pretty interesting that we're introspective enough to even gauge ourselves this way, aside from the bigger picture. It's a matter of what goggles you choose to wear.
Also, many other species don't necessarily "live in harmony", as if that's the working goal. Introduce one species to an environment where it has few predators and a good food source, for example, and you'll see just how quickly it breaks down and overruns that ecosystem, instead of working to be one with it. With no real roadmap to our purpose, our success has its pros and cons, depending on who is judging and in what context.
It would be great if we could find a species similar enough to really compare, though.