2-3 diamond-shaped (i.e. tall body such as gouramis or discus) 2 1/2-3" fish with nice color (preferably some blue because they really bring out the tank) that stick together and can be kept with smaller fish and don't cause chaos. This is what I've been having the most trouble finding! I was almost thinking about Discus but they're just too freaking expensive!
1-2 schools of some sort of small tight-schooling fish with color that offsets the larger ones.
(x-posted to fish communities)