I would recommend clownfish, you have to have clowns. Avoid damsels as they are mean little monsters. Other than that I say every tank needs to have a balance between swimmers, chillers, rock crawlers and sand sifters. By chillers I mean fish like clowns or firefish that tend to stay in one small area of the tank. In my 90g I have 2 clowns (chillers) 1 mimic tang (swimmer) and two gobies (engineer and diamond both sand sifters) and a mandarin (rock crawler). I would recommend avoiding tangs in a 75 (or in my case a 90g same basic tank) there are some you could do however like a kole yellow eye. You could also get a foxface but I find them to be timid and hide unlike a tang always swimming.
In your tank maybe a pair of clowns, small tang like a kole, definitely need a sand goby maybe even a pistol shrimp pair, smaller wrasse like a mckoskers or get a trio of anthias, if you have a sump planned you should plan to have a mandarin dragonette (most beautiful fish hands down)
