Green Terrors are fab... just have to watch the aggression when they mature... they can live up to their name, we keep them, and well worth keeping 8)
Nicaragua Cichlids are nice when mature, the males and females colours are fantastic.. we have a pair of those... they look nothing as youngsters but are stunning when they come into their own with colour...
Quetzals (Red Heads) are more common now... they can be a real pain in the butt if you are keeping an aggressive community tank... We had 4 nice size ones, and one decided to try and carve everything up in the tank, including it's own species... you often see people trying to sell them on TM and hubby has had people coming into the stores asking if they are interested in taking their Red Head on.
We have Geophagus steindachneri, they are gorgeous fish, full of personality... something a little different.
It's great when it's time to hunt around and find what you want 8)