I agree with Jerry W about the Majestic Angel. Some others that come to mind for me are:
Apolemichthys trimaculatus
Apolemichthys xanthopunctatus
Apolemichthys xanthurus
Apolemichthys griffisi
Apolemichthys arcuatus
Pygoplites diacanthus
Genicanthus watanabei
Genicanthus bellus
Genicanthus caudovittatus
Genicanthus melanospilos
Genicanthus lamarck
Chaetodontoplus mesoleucus
Obviously some of these species have require cooler water and can be difficult to maintain in the average aquarist's reef.
Also, it seems to me as though you may have too much rock in your DT. 275 pounds of rock in a 150 just seems very high to me. But as long as there is ample swimming space you should be fine.
~Michael