well, phosphate remover has become pretty popular lately, but i never felt a need for it. folks would tell me you need to use this in order to get good color in your sps, but my sps looked just as good as theirs. i'm sure there are situations where it's necessary, but i don't think they are as common as folks make it out to be.
as for carbon, yes, i like to run carbon. it really "polishes" the water nicely.