You want a mix of snails -- astraea, nassarius, trochus, nerite and turbos are all good choices. Some people like hermit crabs, some don't. Hermits will end up killing some snails here and there, that's why some people pass on them and get a hermit-free CUC. Emerald crabs are good if you have algae. Cleaner shrimp and peppermint shrimp are important down the road, but not right away. And I think everyone needs a brittle or serpent star. There are lots of other neat cleaners, but those are the basics.