depends on the cichlid. there are south american cichlids like discus, angels, and oscars on the large size, then there are rams and apistogrammas on the small side for examples. if your wanting something like african cichlids then options are limited due to agression. haps and peacocks tend to be the more gentle kinds. thats if you are wanting to do rainbows with them.
I would suggest going with the largest tank you can afford and have room for personally. the reason i say that is if you do happen to get fish that don't go well together on accident then they have room to get away. also if there is a water issue in a small tank the issue is drastic and sudden. in a larger tank it seems as though you have more time to catch and correct the problem before it leads to deaths.
As for a colorful community tank there are MANY fish to go with. I would say neons, apistogrammas, rainbows, endlers, guppies (if you don't mind the constant breeding), Rams, then the less colorful but interesting are things like hillstream loaches, panda garras, dojo and kuhli loaches, banjo catfish, cory cats, knife fish. those are a few suggestions off the top of my head.
for africans again alot of choices such as flametails, acei, yellow labs, mainganos, johani, dolphins, brichardi, assorted peacocks like the electric blue red shoulders i bred for a while. those are all fish that i have had at the same time and had good experiences with. with the brichardi they can take over a tank if they are able to breed succesfully. they can have 50+ babies in a batch and each generation with help protect subsiquent generations. the reading i've done on them says they have been found in the wild of schools of 1000+ fish.
African cichlids is a huge family. I didn't even get into a chip of the icberg thats the size of antarctica that is the african cichlid family. africans come from 3 of the great rift lakes in africa and just in lake malawi there are over 6000 species ranging form an inch long to several feet long. it can be overwhelming. my suggestion is to research the fish you think are interesting and look on google or on this site at tanks others have made to get ideas. it never hurts to steal others ideas and modify them to make them your own
Also if you decide to go with a comunity tank make sure the tank gets cycled before adding any delicate or expensive fish. $1.50 don't seem like much for a fish like a neon but if you go the way i did with getting 30 of them it adds up and if you do that without the tank being cycled it's like taking the money and flushing it. Also if going with a comunity tank I suggest looking into doing a dirted tank if live plants would be something that would interest you. it adds to the cost of the lighting but besides that it's very low cost.
I hope i gave information that is useful but not overwhelming