Hippos are nice, but can sometimes be aggressive, not as much as Picasso triggers though, I would avoid them all in general. You could go with aggressive and beautiful (triggers etc), but your corals will be in danger, just depends on the particular trigger, regal etc, but a calm tank is much more safe and relaxing to observe. IMO if you really want the best and most beautiful for your good sized tank then I would go with the following (I will just go into the main display fish and leave out cleaners, gobies, blennys, wrasses etc because there are too many strong opinions on here about them and I am not looking for a debate, just want to help you explore viable options:
#1 Powder Blue Surgeon (beautiful and wicked smart fish, more indo-pacific, but so is the lipstick. My personal favorite)
#2 Blonde Naso (strong, hardy and fast fish, needs a lot of tank. Make sure you buy one at least 4" to start or they have a tendency to starve without continuous food source, >4" will be fine though).
#3 Unicorn Tang (one of the smartest I've seen and loves to lead a peaceful community)
#4 Powder Brown (Harder to keep, but a definite addition for a stable tank)
#5 Yellow Tang (Very hardy and beautiful, but can be a real PITA if you don't add them together, smaller than current population and and last).
#6 Longhorned Cowfish (Now we are getting into the more timid, but really cool fish. I would be careful by adding him to a stable tank and toward the beginning. He can get huge, but that will take years. I love this fish, had to include it)
#7 Purple Sailfin Tang (very cool looking fish, but also territorial, somewhat like the yellow tang in that way, but even more aggressive. Had to add it because it is an awesome indo-pacific fish and some keepers will tell you it is not a problem with their populations and corals. Add him only if you have a lot of algae for him to graze and a tank that will keep him in check [I.E. Unicorn leader] I might not add him and a cowfish).
This would be an impressive population indeed (#s 1-5 as definites). Adding them all at full size would be a bit much for a 210, but small-med will grow for years and you can see how temperaments mesh.
Good luck with your tank and let me know how it goes. HAPPY NEW YEAR!:bdaysmile::celeb3: