All of my fish get along very well, even the gouramis and the angel. My angel is very passive and never chases anyone at all, but I've heard their personalities can vary and, like with most fish, some can be more aggressive than others.
In fact, my gouramis tend to follow Kai, my angel, around the whole tank almost constantly. My angel has never even nipped another fish, but, like I said, some angelfish probably have the potential to be absolute bullies, just like with any other fish.
Oh, by the way, I recently bought this conditioner called Algaefix because my tank water turned a dark green from the heat outside and from the window nearby. I put the amount recommended in yesterday, and within an hour the green was gone and today the tank water is clear as glass, literally: