School Suggestions...

Im in the process of building a rather large tank for a customer and was looking for suggestions for various schools of fish. So far I was planning on putting in 15 semilavartus butterflys, 15 pakistani butterflys, probably a school of lookdowns, and Im trying to decide what type of tang schools I should use? There will be the usual large angels as well. Any suggestions??? What would you put in your dream tank?
Thanks:Kyle