Pros: Durable cord, great dynamic range, almost completely sound-sealing, good accessories, fine value
Cons: Cord tends to stay coiled, may be a bit bright for some people without equalization
The bottom line: My favorites for travelling. Preferences vary, of course, but I don't understand why some people have problems with these.
Let me say up-front that the earphones I'm reviewing are the super.fi 3 Live Pro earphones sold by Radio Shack. These are often available for less than $70 and I suggest you also check eBay or other on-line sources to get the best possible price.

Other earphones and headphones I own and listen to regularly include the super.fi 5EB, Sennheiser HD595, Sony MDR-SA3000, Grado SR125, Grado SR325i, and the Shure E2C. I most often use these with a Little Dot II++ tube headphone amplifier, Practical Devices XM4 headphone amplifier, Gary Ali's PA2V2 headphone amplifier, and the Twinstarr Apheared headphone amplifier. My primary sources include a Cowon iAudio M3 player, with OGG files converted at 192 Kbps (target).

When I fly or travel, the super.fi 3s are my preferred earphones. I find them to be very efficient, with an excellent tonal balance and dynamic range. They do tend to sound a bit bright, but this can be touched up slightly with the equalizer function of my player. When properly inserted into your ear canal, they seal out ambient noise very effectively, making "noise cancelling" units totally unnecessary.

Getting the proper seal is the trickiest part. Most people initially select one of the rubber ear cushions (seals) and stick with it. You really need to spend some time listening with each size to find out which one suits you best. Also, be prepared to use a different size in each ear, if that works best for you. The cushions that came with the super-fi 3s are actually slightly different from those that came with the super.fi 5EBs, though they appear to fit interchangeably on the earpieces. I found it helpful to swap between the two models for the best fit. I have _never_ had any problems switching the cushions from unit to unit. They slide right on and off for me.

One reason I like the super.fi 3s is the durable cord. The cord is semi-transparent and about twice the thickness of the cord on the super.fi 5EBs. The cord is also replaceable, unplugging at each earpiece. Unfortunately, the downside to the robustness of the cord is its tendency to stay curled after being stored. You have to spend a second or two straightening it out after taking it out of the carrying case. Another idiosyncracy is that the thicker cord makes it more difficult to bend the wire inserts at the earpieces to your preferred position. (This wire is what loops behind your ear with the cord to hold the units in place.)

The super.fi 3s come with a nice metal carrying case, spare cushions, an airplane adapter, and a cleaning tool. Use the cleaning tool as needed and wash the cushions regularly.

I'm very happy with these earphones and don't have any hesitation in recommending them to others.