Bret-I've polished more than my fair share of turds in my day! When I first started out, probably only 60% of the vehicles I was doing had clearcoats. Now it is probably 95%! vmunoz is right that DACP, SFP and HP is more than adequate for the vast majority of the vehicles you will come across.
I do agree though that at least one product more aggressive than DACP should be part of your polish inventory. I'd also add a glaze like Vanilla Moose, GEPC/SEC or Poorboy's PwC to add even more pop prior to sealing the paint....which makes 5-6 products, just like you said! :up
I've got Diamond Cut, Blue Moose (a yet unreleased compound Clearkote makes-quite aggressive!) Scratch X, DACP, SFP, HP, Vanilla Moose, PwC and AIO.