I assume this will not be your only tank? If it's your only tank I would say mixed reef or mixed leaning towards a specific type (like "mostly SPS" or something). If it is not your only tank you could be more out of the box stuff.
Maybe a species only tank, one type of coral but as many variants as you can find.
Floating aquascape would be cool.
Could mess around with NSA if you haven't already.