(Repost with permission)
Good Beginner Fish
Angelfish
Coral Beauty Angelfish [Centropyge bispinosus] (probably the hardiest of all the dwarf angels but they can nibble on corals and clams)
Half Black Angelfish [Centropyge vroliki] (see Coral Beauty)
Pygmy/Cherub Angelfish [Centropyge argi] (see Coral Beauty but
consider that they are often meaner, the same goes for most other similar shaped Pygmy Angels)
*Angels can be a little prone to disease but are otherwise pretty hardy if given a good diet
Blennies
Bicolor Blenny [Ecsenius bicolor] (great little fish with lots of personality that can help with algae problems, only problem is they're know to sometimes take a liking to munching on corals and clams, procede with caution)
Tail Spot Blenny [Ecsenius stigmatura] (in most cases probably a better choice all around than the Bicolor Blenny, though they aren't quite as boisterous which can be a good or bad thing depending on your perspective, less commonly available)
Linear Blenny [Ecsenius lineatus] (see above)
Cardinalfish
Pajama/Spotted/Orange Lined Cadinalfish [Sphaeramia nematoptera most common] (peaceful, disease resistant, and hardy, Cardinalfish in general are good choices just be a little more leary of Bangaii Cardinals that are new to captivity and red nocturnal varieties)
Clownfish/Chromis/Damselfish
Tank Raised Clownfish [Amphiprion sp.] (percula and ocellaris stay smaller and are les aggressive, Skunk clowns can be more peaceful as well, Maroon clowns tend to be the meanest, and all the others usually fall somewhere in between)
Green Chromis [Chromis viridis] (very peaceful and will school, but it is becoming pretty clear that in smaller schools they will sometimes pick the weakest member of the group off one by one, perhaps larger schools of 6+ in larger aquariums would eliminate that possibility)
Yellowtail Damselfish [Chrysiptera parasema] (can be aggressive but not quite as mean as most other Damselfish, add them as one of your last fish)
*In general Damsels are very hardy but the majority of them get far too mean to be considered good inhabitants in most tanks
Gobies/Dartfish
Firefish [Nemateleotris decora/magnifica] (great reef fish, just be weary when keeping in groups as they can turn on one another, singles or mated pairs are you best bet, they have been known to jump but it's not a big problem)
Scissortail Goby/Dartfish [Ptereleotris evides] (almost identical to Firefish in care)
Yellow Watchman Goby [Cryptocentrus cinctus] (tough as nails, very comical, peaceful, but a little shy and require some sand to burrow in, make sure your rocks are stacked securely)
Pink Spotted Watchman [Cryptocentrus leptocephalus] (see Yellow Watchman)
Gold/Blue Neon Goby (peaceful and often avilable as tank raised, keep as mated pairs or singles unless you have a large aquarium)
Hector's Goby [Amblyeleotris hectori] (similar to Rainford's but seem to accept prepared foods more often, just make sure they're eating before purchase and keep them with more peaceful fish, they will also sift food from your sandbed and tidy it up so it's best to have a sandbed)
Pseudochromis/Basslets
Royal Gramma [Gramma loreto] (kept singly they are peaceful, but the biggest drawback is their shyness, provide plenty of overhangs, they may also do best in aquariums with a little less intense lighting)
Pseudochromis [springeri/fridmani/flavivertex/aldabraensis] (very hardy and disease resistant, however can get quite mean, they are fairly well behaved as long as they're the last fish added and you avoid similar size/shape fish, frequently available as tank raised)
Pseudochromis sankeyi (same as above except far more peaceful)
Tangs/Foxfaces
Zebrasoma sp. [Yellow, Purple, Scopas, Sailfin] (these are the hardiest of the tangs in my opinion, still not great beginner fish, but if you must have a Tang these are the best choices, be sure to provide plenty of green stuff for them to graze on and feed them often to stay plump, as a basic guideline it's best to keep these in 75 gal. or larger aquariums with the consideration that they might outgrow those down the road, they can get mean so make them later additions)
Foxfaces/Rabbitfish [Siganus vulpinus is the most common] (these fish can get quite large so be sure to research if your tank is large enough to house one, they're great at algae control, more disease resistant than their cousins the Tang, and generally more peaceful, also keep in mind their dorsal spines are mildly venomous)
Wrasses
Six/Four Line Wrasse (can get mean much like the Pseudochromis, but also requires a sandbed to borrow in, sometimes these will consume undesirable flatworms)
General Notes
*Keep in mind that there are plenty of other fish that are suitable to beginnners, I've covered most of the staples. You'll find that most of these fish are easy to find at a local fish store and are fairly reasonable in price. As a beginner don't spend a lot of money on some rare fish just to watch it die from a common beginner mistake.
*Fish selection is one of the most important aspects of this hobby. Select specimens with bright vibrant colors that are active and overall healthy in appearance. Avoid things like torn fins, strange spots or lumps, sunken in bellies, and sores or red marks. It can also be helpful to see if the fish eats before taking it home.
*Quarantine tanks are an important aspect of marine aquarium keeping. No matter how healthy and disease resistant your fish looked at the store things can still go wrong. A quarantine tank will help you keep the fish in your display free of disease and help ensure the longterm survival of newly aquired specimens.
Peter Eichler (Reef Central)
Fish to Be Avoided - Part I
Fish to be Avoided - Part II 
A List of Good Beginner Fish 
jb
