Lake Tanganyika cichlids are very beautiful, but sometimes hard to find. Call around to make sure you can find them before deciding on them. :-) Most lfs don't carry them and a lot of times people have to order them online. Also, if you get a pair of Neolamprologus brichardi and they pair up, they will take over the entire tank when they spawn, (this is from experience and what others have experienced). They also keep spawning and the older fry will take care of the new fry. They are best keep as a species only tank because of this.
Yellow Labs are Mbuna. They can get along with Peacocks, but they are about the only Mbuna who do. Mbuna are very active and tend to stress out Peacocks.
People that do an all male tank go with the peacocks because they don't need females to color up. Those are beautiful tanks!
Yellow Labs and/or Ps. Acei are a great Africans to start with. They are mildly aggressive and get along with most all Mbuna. If you go with Mbuna, look for fish that have the same basic temperaments. If you have a mild one like the Lab and get some, say Kenyi, Johannii, or Bubble Bees that are extremely aggressive, you will end up with some very beat up Labs. Its best to start with the least aggressive until you get some experience in keeping Africans.
Here is a link that shows a lot of the Mbuna's, their max size and temperment.
http://www.cichlid-forum.com/profiles/c ... .php?cat=2
Here are the Peacocks:
http://www.cichlid-forum.com/profiles/c ... .php?cat=3
http://www.cichlid-forum.com/profiles/i ... p?region=T
This is a good article on mixes for certain tank sizes, to give you an idea:
http://www.cichlid-forum.com/articles/c ... er_55g.php
Good articles on African Cichlids:
http://www.cichlid-forum.com/articles/i ... n_list.php
My best advice to you is read all you can about the groups you decide to go with. Try not to impulse buy, that way you wont get one and take it home to have it beat the crap out of all the others. Also, don't mix lakes. Each lake has a different pH and hardness level, and their diet requirements can be different too.
If you decide on Mbuna (they are the easiest to find in stores) the best way to set up is to add the least aggressive group first, like the Labs, so they can establish territories before adding a more aggressive group. Most all African cichlids are harem spawners so if you plan to breed (and they will whether you plan it or not LOL) the best mix is 1 male to 3-4 females. If you only get 1 male and 1 female she will end up harassed to death because males always want to spawn! A group of girls spreads out the aggression of the male.
My setup is 4 main groups of 1 male to 2-4 females. Then I have 2 males of a different kind as the odd fish. I always have at least 1 or 2 holding females (they hold the eggs in their mouth after spawning until the fry are done with the egg yokes) with this setup. Right now I have 4 holding. If you don't want the fry, they will release them into the main tank and the adults will eat them.