Saw the size after he replied, I think Rams are a good one though. I suggest cichlids because they are versitile. They show awesome predatory behavior and are responsive to their keepers while most can still be good comunity fish. I think they are the embodiment of what the typical MONSTER fish keeper would want, No? So, sorry if I'm biased and thank you for the correction.
I had a look at Wolfs just then Blue Phantom, and they get to 76cm!
I don't think that would fit in my tank.
I've heard Oscars are pretty good fish though.