I would recommend that you go to Live Aquaria's website, where you can sort fish by tank size, aggression level, and level of difficulty. Start there to find out what you like and then spend time researching each fish. I wish I could be of more specific help, but my experience is with nano tanks and there is much more you could put into a 50g. If I had a bigger tank, I'd definitely house a wrasse or two. Anyhow, if you can come up with more specific ideas, it will be easier for us to help.
Damsels are often recommended because they are hardy, but... they are total nightmares. They are notoriously aggressive and have been known to harass and kill much larger fish than themselves. Thing is, there are lots of species in the damsel family, including clownfish. A clown should not be as much of a terror as say, a yellow tail damsel, but they can still be rather territorial. What's most important is that stocking the tank is done slowly and carefully. First inhabitants should be the more peaceful fish if you want them, and they should have plenty of time to get comfortable in a tank before a potential aggressor is added.
Agreed, stay away from Damselfish if you want to keep a variety of fish.
I also agree with spending some time on and checking out minimum tank sizes, temperament, etc. Other sites lie through their teeth on minimum tank size requirements.
Among the easiest fish to care for that are suited for a 50 gallon tank:
Clownfish (stick to Occ and Percula varieties as the others are too aggressive) Cardinalfish (I would say the Pajama is the easiest of the bunch to keep) Royal Gramma Basslet Orchid Dottyback (This Dottyback only as the others are just plain mean) Firefish or Dartfish (Just be aware that they are easy targets for bullying and may spend lots of time hiding) Gobies Blennies
Melanurus Wrasse (aka Hoeven's, Tail Spot or Pinstripe Wrasse)
Red Lined Wrasse
Possum Wrasse/Pygmy Wrasse
Melanurus Wrasses are my favorite of the bunch (just be aware that it will occasionally eat small inverts such as hermit crabs, snails and little shrimp). It would easily be the centerpiece/showpiece for your tank. Here is a vid I have of a Male and Juvie pair that I had in my 90: