You don't have to pay the earth to get smooth, uncolored and linear sound from headphones that's similar in neutrality to Axiom speakers. I've owned the Grado SR125's for years -- they are comfortable with wide-band uncolored sound. About $150.
For amazing sound quality vs. price, don't overlook the Koss PortaPro --smooth, uncolored, with a slight bass boost in the lower octaves-- at about $39. The temporal pads and lightweight design make them extremely comfortable for long-term listening.
Comfort and fit is everything. There's no point in getting headphones with excellent sound quality that you want to tear off your head after 15 minutes because of discomfort.
Axiom Resident Expert