AUDEZE LCD-2 pads (new soft ones)
FiiO e07k: Bass +6db, Treble -8db
This setup actually now makes rock music sound better and more enjoyable than the Panasonics and Electro still sounds amazing! I can honestly say I am not sure how it gets any better than this (for under $400).
Welcome to Head-Fi! Nice write-up, and you should continue to enjoy the K550. They are great sounding headphones. If and when you do itch for something with a little different flavor (sorry about your wallet and all that...) you might look into the HE-400 as it's currently sitting at ~$250, especially if you really like electronic music. The FiiO would drive it fairly well.
I do recall the K550 sounding especially good with rock and elecronic. Nice choice!