tank size is a relative thing depending on what country you are in, forums like this which are majority American users will tell you to get bigger tanks for fish that European forums will say don't need. Its because larger tanks are cheaper over in America whereas in Europe anything above 3ft usually costs a retarded price unless you get one made or buy one secondhand from the internet.
The thing is, if a fish is too big for a tank, you will know. Anyone can look at a tank and see if the fish is too cramped, yes you could get a trimac or a devil in a 75, but theres a possibility you will have to upgrade in the future, and as long as you don't mind getting a larger tank down the line you can go for pretty much any of the larger cichlids, they all have the same interactive personalities. The reason why i tell you about tank sizes being different around the world is because I'm pretty sure you will be told to go out and buy a bigger tank before you even need one.
some other cichlids i could recomend to you boosh96 would be
Larger
green terror
jack dempsy
jag
-smaller... possibly-
severum
motaguense
loiseli (however that is spelled)
Salvini
You could go for a chocolate cichlid, or perhaps even a pike of some kind,
just google around the different fish and search them on here . and be sure to show us some pics when you set up the tank and buy the fish.
El