Both African and American cichlids are stunning, beautiful fish. Which ever you choose, you have the potential to make a
very impressive set-up.
It totally depends on your own opinion on what you like, and what you want. Also, what you can get hold off lol... Have a look around, there's plenty of pictures. Have a look on Cichlid-Forum. Also, the pinned topic 'Members Tank Pics' on both African and American sections. See if any take your fancy....
I keep Afrcians, i love them and wouldn't change for any other fish. I noticed someone mentioned 'they lack personality' .... trust me, thats soooooooo not true lol. A fully stocked African set-up is
never boring.
You cant get anymore colourful than Afrcain Lake Malawi Cichlids without going Marine. Especially the Peacocks which can be stunning in colour. For your tank size, Lake Malawi Cichlids would be ideal. A little on the small side for Tropheus or Frontosa though which are also beautiful Afrcian fish.
Godd luck with which ever you choose