Last week I got fed up with the hard Apple white headphones that came with my iPod Mini and I invested in some decent Sony ear-bud style headphones. Now for those of you that do not know what ear-buds are these are the little headphones that are meant to rest inside your actual ear canal rather than just sticking in your outer ear or held in place by a band around your head. These take some getting used to but the overall effect is breathtaking.
When you first try them on you have to get used to the mild pressure and the overall feeling is exactly like wearing earplugs. These are great at canceling out most loud background noise because it really works quite like ear plugs. The sound is quite an upgrade over the standard Apple headphones. There is a single cord that goes to the left ear and there is the right ear connected to the left. The cord is tangle resistant and it looks like you have small cords sticking out of your ear and into your pocket. The ear-buds are rather soft with a loose rubber coating that shapes to your ear canal and it is quite comfortable to wear for several hours at a time.
It does sort of suck to eat anything crunchy with them in because it is quite loud and will resonate rather unpleasantly. I make sure to make sure I never crank it too loud but it reproduces an incredible sound for a quite reasonable $40. If you dished out over a two hundred bucks on an iPod, PSP or other digital music player it really is worth it to upgrade to some decent headphones to the most out of your investment. Apple may be way a head of Sony when it comes to digital music players but the if you are rocking an iPod it is worth it give up the white earphones. It is like having giant speakers mounted inside your head.

I have a pair of MDR-EX70's which are very similar to yours. I love them. They really have great dynamics and improved bass response for a fairly cheap set of earbuds (when compared to some Shure, Etymotic, and other sets of high-end earbuds).
I highly recommend the Sony buds as well!
I've had the Apple Noise Cancelling Ear-Buds for a while now and they sound amazing as well. I mow my lawn with a big ridable and I can barely hear it because of those babies! Mine were $40 as well. Good choice.