Hi Marteau. The size of my tank is close to what you're setting up. I have a 53 gallon open top Elos with a 7 gallon sump (picture and video below) You can see the list of fish I have below. Tank has been set up for 15 months now. I know an open top limits you as to what fish you can have in it, but covering it with anything is not an option for me, because the reason I bought an open top, is because of the beauty of it. What I've tried for fish and how they did.....
Coral Beauty.... I thought this angel was one of the safer ones as far as nipping corals, and didn't think it was nipping much at all. He would quickly just pass by corals and act like he would taste them, but wasn't interested in them. He did the same with my Crocea clam. Well, that clam wasn't opening as much as it normally would open, for a couple months after I added the CB, and I had a couple SPS corals that had no polyp extension. I decided to pull the Coral Beauty out of my tank, and the next day, I couldn't believe how open and beautiful my clam was!!! And it has stayed that way since I pulled the CB out of my tank. Within a couple days of pulling out the CB, the SPS also regained the polyp extension.
Firefish. I knew they could be jumpers, but I was told by a couple guys at my LFS, that they had them in an open tank and they never jumped, so I took a chance. I had a purple firefish for 4 months and one day he jumped. I then got a red firefish, and also had him for 4 months, and then he jumped. So...won't be trying another firefish.
Tailspot Blenny - Very cool fish. I had him for about a year and he mysteriously died one day.

I definitely want another one.
Yellow Coris Wrasse - Beautiful fish, extremely bright yellow. He was exibiting some strange behavior so I brought him back to the LFS. He was constantly going to the surface of the water and splashing water EVERYWHERE!! He was making a big mess. Salt water all over the glass of my light fixture, dripping down the outside of the tank, etc. Other than that, I loved him.
Pygmy Possum Wrasse - I wanted something unique looking, and thought these were really cool looking. Neat fish, but he hid a lot, especially after I added the Coral Beauty. The CB was such a FAST active swimmer, that I think it made the possum hide. He hid a LOT more after I added the CB. The Possum Wrasse mysteriously vanished after I had him for about a year. I decided not to replace him because I had hopes of trying a Mandarin and didn't want a wrasse to compete for pods.
I have what I feel is a great mix of fish now. They are all peaceful and get along great. They all stay out in the open which is important to me because I am limited on how many fish I can have with a 53 gallon tank. What I have now....
Longnose Hawkfish.... what a COOL FISH!!!! Great personality. Very bold but peaceful. Looks cool how he perches and then darts off.
Royal Gramma, I love the combination of colors and how vibrant he is.
Bartletts Anthias. Gorgeous bright active fish.
Wildcaught True Percula and a Onyx Percula that I just picked up a couple weeks ago.
Psychedelic Mandarin - I waited until my tank was over a year old to try a Mandarin. I like the looks of the Green Mandarins more, but I had read that Psychedelic Mandarins are easier to get to eat frozen food, and since my tank is only 53 gallons, I thought that was important. I picked up a Psychedelic Mandarin that I saw eating frozen Mysis at the LFS. I brought him home about 5 weeks ago. I didn't notice this at the LFS, but when I brought him home, he looked REALLY skinny and his stomach was sunken in. I didn't have a lot of hope for him surviving, especially because of the size of my tank, and even thought I've added some pods a few times to my tank, and added some a month before I brought the Mandarin home, I never have been able to spot pods in my tank, so that worried me. Luckily, not only has he survived, but he's fattening up nicely !! His belly no longer looks sunken in. He's doing really well. I use a turkey baster to put some frozen food right next to him, and he comes right up to the turkey baster. Last night he was eating frozen blood worms with gusto, and he also eats frozen enriched brine and mysis. There's a video below of my mandarin. That video was taken about 3 weeks ago, and he's filled out a lot more since then.
VIDEO OF MY TANK
VIDEO of my LONGNOSE HAWKFISH
VIDEO of my PSYCHEDELIC MANDARIN