Headphone Purchasing Decision, Please Help

What quality of files do you use? I'm not experienced here, but if you use 256 or 128kbps you might not want to jump into 200$ headphones with a 150$ amp to make bad files sound good.

Also, the e11 is just an amp I think, you would probably want an amp/dac (the DAC basically makes the music instead of the ipod, which will give you not to great quality).

Find someone with more experience to ask for specifics, I'm still learning myself.

Honestly, not to be an M50 fanboy or anything, but M50s seem much more suited to your genre preferences. The DT770s to me were too laid back and spacious rather than engaging and fun (of course, I'm talking about the Premium versions, not the Pros).

M50 + E5 bass boost ($20) = awesome to me.

Again I have no idea about DT770 Pros since I used the DT770 Premium 250OHM (and, along with that, unamped because I was planning to upgrade to an amp then ran out of money so I returned it :)).

Also I don't find portable amps to do jack honestly. Couldn't tell the difference between E7 AMP / DAC connected to my phone / PC (with the DAC vs'd my integrated piece of crap). No idea for E11, but personally, I wouldn't do it really.

Also if you do go for M50s, you can get them for under $130 new if you wait (they're at like $160 atm) or buy them used for even cheaper.

If you ever plan to use the phones portably, then just cross the DT770s off your list as they're insanely huge and insanely chip prone (I barely dropped it on concrete and it chipped). M50s worked much better to me in that situation, but I'm already upgrading to HD25s, so maybe that's even saying something :).

The new skullcandy headphones are surprisengly detailed and suited well for the above genres but i will recommend some other headphones too like DT770, Ultrasone HFI780, Klipsch Image ONE, Monster HD Solo, Denon D1100, Bose on ear and JVC on ear.  The AMPs does make big difference like gives more volume, Clarity, tightness,more bass and bigger soundstage. The Pure Cryo dock cables makes easier to achieve all of these qualities than pure silver cables, so cables are important too for final soundsignature. I think E11 willbe great edition in the setup for better soundquality and more power.

HFI-780 or HFI-580 would both be good choices in your price range for the music you listen to, and both are adequately driven using a portable media player by itself, but scale well if you decide to add a portable amp in the future.  Instead of buying the amp along with the headphones, get just the headphones and give them a listen on your iPod; if you're satisfied, leave it at that and you won't be out money for an amp. 

Low-bitrate music can be an issue, but I didn't find 128kbs unlistenable with my HFI-780s - sure, not as nice as 320kbs or FLAC, but headphones are the biggest part of any setup.  I'd rather listen to 192kbs music with nice headphones than FLAC with cheap headphones.