Cichlids are a very broad, populated family of fish. What general area are you looking for? If African, I would recommend Lake Malawi Mbunas. Labidochromis caeruleus (Yellow Lab) are very bright yellow, with black fin highlights and very peaceful for cichlids. Ioddotropheus sprengerae (Rusty cichlid) are dimorphic, with the males being much more colorful than females and also peaceful for cichlids. There are several reasonably peaceful, colorful Mbunas. You could also check out peacocks, where you'll find some very colorful fish.
For New World cichlids, you could try Thorichthys meeki (Firemouth), Aequidens pulcher (Blue Acara), or check out the Apistogramma species, smaller Geophagus species, or Microgeophagus species. All are relatively peaceful, colorful, and interesting.