who is it intended to? It has a true sound like you want when you do music editing or mixing, and need to be able to clearly hear how the instruments sound. The lack of bass will work for your advantage as well.
But who does that kind of work with an i-pod?
At times these headphones sound very good, when I have tinkered my mp3-players equalizer just right, I even get some bass when I loosen them a bit, let them come down and slightly forward so that they close over my ears as they should; and when I have my finger constantly on the volume button.
After three days I get tired of adjusting one of these things every time one of these things were not exactly right and it started sounding just awful.

The point is, as good as these phones potentially may be... (Or rather, adequate, as even with all things right I don't think they sound as good as I have grown to expect a Sennheiser to do), You won't be able to just put them on and the forget about them and listen to your music.

Also, to be fair, I have to add that much of what I didn't enjoy with these headphones may have been the inadequacies of my mp-3 player and some less than perfect mp3 decoding. But, these are exactly where I would be using this set. When home next to my amp I'll trust my good old Sennheiser HD-25.

The inadequacy of bass bothered me to some extend, although that was mostly helped with adjusting the set so that it would close better over my ears - it is extremely important that this set is placed exactly right. What disturbed me much more, though, and was ultimately the one determining thing that made me not want to hold on to this set was the harsh mid-range... piano and some vocals just come out scrreching and disrupting that terrific harmonious sound that you've spend the last 1/2 hour adjusting your set to achieve.

For me, the PX200 works much better. comapred side by side in ideal circumstances, PX200 will win, but the PX100 is the grab and go headphone with excellent sound. The bass, although it is not the sharp and deep one that you get with px200, is harp and deep enough - and more imprtantly it is always there, no constant adjusting needed.

PX200 is an adequate headphone for long flights when you carry a good music source (it sounds a lot better with my CD walkman than with my mp3 player). PX100 wouldn't work here, as it leaks so you will drive your seating neighbor insane during a 12-hour flight.

Edited to add:
Just before sending this set back, I tested it side by side with PX100 and my Sennheiser HD25SP. comparing HD25 really made it clear why I never really liked the PX200 despite its incredible crispness. The mid-range is so harsh is is painful, almost screeching. And this in comparison to a quality Sennheiser set. Again PX100 wins.

There are a couple of things to rave about with the Senn px200. Its most charming feature is its compact foldable design. Secondly, its thd % is low, so sound is very very clean. The flattery stops there.

I waited patiently like a saint for the bass to present itself after the "burn-in period." Well, the bass never really gets to where it needs to be for actual listening enjoyment. I didn't even have a moderately good time with these. Bass which isn't there to begin with will not miraculously appear all of a sudden...there is no bass, ABSOLUTELY NO BASS with the Senn px200 period. I'm no basshead by any means, but come on. Where the heck is the bass?

Alongside its basslessness, the Senn px200 is also a bright little performer. Ouch...that's two strikes...no bass and shrill on top of that. Hmnn... needless to say, I sent these back to Amazon.

Seriously ponder whether these are worth the purchase. Consider the Sennheiser hd 202 for a closed design headphone. For about 25 dollars, it's great-sounding and easily portable.

I bought these a little over 6 months ago. This is the best headphone purchase I've ever made. I use them at the office for listening to music. For the price, you can't beat them. They produce great quality sounds and the do an admirable job blocking out other sounds too. Full rich sound, good for everything from dance to classical.

The industrial design aspect is simply amazing. They are very comfortable to wear. They collapse in to a great form factor for either putting in your desk or in your bag. The cord, itself, uses a sort of sliding binder to either keep the right and left cords neat when the headphones are put away. The case is the best I've ever seen for headphones. Everything gets neatly tucked away or wound up so that storage is simple and safe.

Simply a great product

Sennheiser has built an overall ok pair of headphones. Although priced high, these headphones introduce a new, very durable case system. These headphones actually fold up and go into a very small transport case, which seems to stand past lots of banging and hitting.

The headphones are light and quite comfortable. Although these headphones could be much better than what they are, I'd generally call them adequately, they do their job. The sound quality is good, though it misses that so important base.

Think twice before buying these, investigate other options as well, though if you settle on these, I don't blame you.

sennheiser px200 is a good pair of headphones for those who would use them for a portable device. Small, compact, comfortable, they also sound very good compared to what you can get from this size of headphones. The sound is crystal clear and very good for acoustic music. With other types of music you will find them a bit sharp. But if you have adjustable EQ then they are fine. Good bass too. Only a few flaws: do not isolate you from the outside noise 100%; give a weak static noise when used with PC or something more powerful. I use them with my iRiver cd player and they are just the perfect match for it.