My fish list in a 320 gal tank:
Angels: Regal(3), Watanabei(2), Flame(3). Copperband But. Tangs: Powder Blue, Yellow,Chevron. Foxface, Harlequin Tusk. Marine Beta(2), Loepard wrasse(3). A. percula(4- atrio and a spare)
A well run 125 gal tank should be large enough to keep most fish that are available in our hobby. Avoid Sailfin tangs, and tang in the Naso genus. They just get too large.
Yellow or Purple tang should be great. Try not to add tangs of the same Genus together. I recently remove a Purple tang because he was beating up my Yellow tang after 4 years. They were both added when they were just over 1 inch quite a few years ago. Power Blue or Power Brown tangs are great fish, you can add one of the two if you feel up to it.
Harlequin Tusk is the definition of a show fish, IMO. Beautiful, hardy, out all the time fish but does have his down side. Mine does not eat my shrimp or small fish, but I feed him well. Hard to add new small fish. Disoriented bite size fish will bring out his killer instinct like you wouldn't believe. He went to bed early so if you add small fish or shrimp, make sure you feed him very well first and add the small fish and shrimp right before the light go out, when he already go to sleep in the rock work.
Harem of Flame Angels are great. I keep a mixed tank, mostly anemones. My Flame angels does not bother any of my corals, anemones, or clams. They are easy to get and until recently easy to get acclimated into captivity. In the evening, spawning of my Flames always impressed people. My regal angels are also a great show fish but they are not easy fish to get to live in captivity initially. Once acclimated, they will do great.
When looking at my tank, non reefers people notice the Harlequin Tusk, Regal Angels, CB Butterfly and the Flame Angels, and of course my Nemo's and anemones.
If you have any specific question, I would be happy ta answer them for you.