Massive C/A cichlids. Jags, Motas, Loisellei, Freddies stuff like that. Or a Severum Community. Uaru is another good community set-up. I was tempted to set up a Uaru community because my LFS has like 10 3"-4" ones for $15-$25 a piece. Cichlasoma Bocourti, Cichlasoma Beani. Also maybe a Geo community.