IMO it really depends on the PCDP. Most bass boost options I've tried have been pretty bad and made the overall sound muddy and the bass boomy. However, on my Denon, I only listen to it with Treble and Bass boost. What PCDP are you talking about? It varies from player to player although the reputation of bass boost in general here in rather low.
punchy bass is very different from the direction you're trying to get to. what you are describing is super flappy and bloated and boomy bass that take over the whole frequency range and destroy all the details.
you should just try some headphones with a different sound signature and get use their sound, preferably oneswith nicer high end and clarity. after that you will realise that the px100 and e2c both originally have a good amount of bass to start with. no need for bass boost.
as for punchy bass, this is actaully a very crave for feature that i seen few in headphones that cost below $100. punchy bass is never overwhelming, it is very tight and controlled. you can hear it and discern it from other instruments. futhermore its response speed is quicker than that of bloated and boomy bass. atleast this is what punchy bass in my opinion.
right now i'm thinking grado, but they actaully have more bass than i wanted. most people like more bass quantity than i do. i find myself enjoying the bass that come from the k501 and eggo (aka very little amount of).