Eric,
First off, I think you made a good choice in both going with cichilds and in turning to a forum like this for help for you first tank.
I am glad to hear that you are not really thinking of oscars or a FH now as a 55 would not really work for such a large fish. A 55 would work well for either a small community of smaller cichlids or it can work for a pair of some of your medium sized cichlids. So I would really decide what you want to do with the tank in that regards.
The cichlids I would research for a 55 beginner are:
Convicts
Firemouth
Salvini
Sajica
Servums
Angels
and Geos
If you are looking for something with a little more activity and somewhat aggressive you could get a lot of enjoyment out of a pair of convicts. They are great beginner cichlids and easy to find. The only problem is that they breed like crazy and sometimes it is hard to find places for the fry. Also even though this seems like a large tank it wouldn't be able to keep much else in there with a breeding pair of cons or really any of the other choices if you did go with a pair. If you decide to do a pair of cichlids the best way to get a good pair bond is to get 5-6 of them and wait for them to pair off and then return the rest.
A community idea that could work is a convict, firemouth, and maybe a JD. That would be a little crowded but could work depending on the individual fish. You will find that what works for some doesn't work for others because a lot depends on the individual cichlids aggression and personality.
Keep the questions coming and let us know what else you need help with.
-Cage
