Newbie here, need help getting the ball rolling...

So within the past few months I've taken the first steps down the road of audiophilia.  I have a few questions, though, mostly about where I should go from here.

So here's my situation, I have an iTouch...with a pair of Grado SR-80i's...and that's it. If it matters, in the meantime I downloaded an app called Bongiovi DPS which is just a nice little app with some sweet preset EQs that seem to pick up the iTouch's slack. I hear that the Grados, and any good head-phones, require an amp to fully experience them. First question, what will some of the consequences be with using the Grados without an amp? What will an amp (mini amp, whatever) do to make things "better?" I'm considering getting a Hifi Man HM-601 as my next portable audio player, but we'll get into that later.

I listen to allot of Dubstep -- not like Skrillex or anything, mind you, like Distance, Loefah, Skream, Burial, the old stuff -- so allot of my music is sub-bass heavy. Maybe it's the lack of an amp, but the Grado's seem to fall pretty short when it comes to bass. I can still hear the bass, and it comes in very smooth but there's no...power, or punch to it I guess you could say; I don't know how else to describe it. From what I've gathered, it's because they're open backed and they "let allot of air in." What does this mean? Also, any suggestions for an affordable pair of cans that are rich in bass yet not lacking in the mids or highs? In retrospect, I think I bought the Grado's on impulse. I kept reading that they were one of the best affordable high quality headphones on the market, and while I think they're AMAZING, I just don't think they're good for the type of music I listen to. Everything accoustic sounds marvellous on them. 

Any suggestions as to any good portable audio players other than the hifi man?

If you were me, what would you buy next?

Thanks! :)