ocellatus said:If you're looking for cichlids, my vote is Kribensis. Small, very pretty fish, non-aggressive, easy sexual dimorphism, easy water parameters, good parents. Fry are on the small side, but easy to raise. 30 gal would be plenty of space.
As viciousconvict suggests, the anabantids are also a lot of fun. Blue gouramis are among the most prolific fish around, and the dwarfs (although I haven't raised them) are so nice.
Good luck!!