you have lots of options in that size tank , one thing i would question is can you keep temps down to sub trop , if not then you are looking to have full tropical species
here are some suggestions that i would use that tank for.
sub-tropical
maculata , poss auranti , asiatica , ornatipinis , pulchra , sp five stripe , stewarti ,
tropical
lucia ,melasoma , africana , obscura ,insignis , large varient of bankanensis , poss pleuro ,
to be honest the only ones i would stay away from is micro , maularoids ,marulia ,straita and barca. it would be the bare minimum for pleuro and auranti that are kept in groups , as pleuro likes more lenght and auranti become aggresive in any thing less than that lenght
amount - as always i would start out with around 6-8 fish and thin out as reqd or if a pair forms , the ones with the most attitude would be pleuro have that snakehead menasing look and are allways on the prowl and look fantastic in a group
cheers col