It sounds like you are a bass head and there is nothing wrong with that. However, AKG headphones tend to be very weak in the bass department no matter what amp you use. That is just how those headphones are designed which is why I personally don't like them. Generally, high end headphones and amps are designed to have a natural sounding bass which is good for stuff like classical, jazz, and classic rock. If you want something with lots of bass, you may want to consider lower end equipment but you will have to sacrifice the clarity and detail of the mids and highs. Check these out:
I heard them briefly at the Sony Store and they had incredible bass impact with no special amp required. They had them plugged directly into a mp3 player. Unfortunately, their demo songs only had bass and no vocals or other instruments so I have no idea if the mids and highs are any good.