show fish

So I have a 75 gal with 100 pads live rock and getting into softies and lps. In my tank now I have:
Blue tang
Blue streak cleaner wrasse
2 clowns(ofcourse)
Scooter blenny
Sand sifting blenny
Damsel.

Equipment:
2 radion 30 pro
2 MP40's
40 gallon refuge sump/skimmer
Ro/Di
Spectrum ATO
Apex (semi set up but not really,lol)
Buddy who owns the LFS is hooking up a 3 part Doser this weekend for Alk Cal Mag

My question is any ideas on that one semi expensive Show Fish I should add. Want it to be a colorful one!!