I like the tuby anenomes and other very colorful corals the longer leafier and more tube like or more movement the better !
Sorry that is a lame description but I am not at that stage yet! I am not sure or simply not had the time to do what I feel is an adequate investigation of corals... The more coral variants and vibrance the better though for sure !!!
It may be cheaper to purchase two 36 inch fixtures versus one 72 inch fixture, plus that way you can tailor your lighting to suit the specific needs (ex: get one mh fixture for the light loving sps, power compact for some with lower requirements)