If you can stretch to $300, you MAY be able to find an Audio Technica ES-10. It would involve a lot of searching to get them new for the price, but it MAY be possible to do. They may also be attainable for that price if you buy used (check the For Sale forums here).
ES-10s have strong, forward bass which is probably the main highlight of their sound signature for you. I love the mids and treble as well, but they will seem recessed on a bass heavy track, because of the forward nature of the bass. Driven straight out of a half decent portable media player, the bass will be tight and controlled, rather than bloated and muddy - a nice plus.
The other advantage of ES-10s are that they are perfectly optimized for portability - 1.2 meter (4 feet) cable, terminates straight into 3.5 millimeter (1/8") connector without an adapter, and can probably be driven to almost all of their potential straight out of an iPod [or iPhone, in your case] (if they're about as good as my Cowon S9). I use them at home too as my main headphones, over HD 555s and HE-5 + EF-5 - the latter of which alone costs about $1,000, and that doesn't even include a DAC.
The earcups WILL feel uncomfortable at first, out of the box, aggravated by the initial clamping pressure of the headband. However, constant use or the 'pillow' method (clamping ES-10s on a pillow or similar surface to stretch them out, loosening the clamping pressure on them without having to wear them yourself).
They are already substantially more comfortable for me.
Edited by Vergex2 - 5/19/10 at 7:01am
I'll probably write a more detailed review on these headphones after significantly more ownership - out of the box they are very nice - and I wonder if they will improve with burn in?