These are fantastic earbuds. I use them at work to surround myself in aural bliss inside my little square cubicle. No loud talker, nose blower, gaffawer, a-hole can interlope my nirvana.

These are 1000% the best headphones I have ever experienced. Yes, I say "experienced" intentionally...this is far cooler than just listening to music. The earphones fit so nicely in your earhole that they create a personal environment unlike any other. You can see the world around you but the only thing you hear is whatever you are piping through the wires. Extra bonus...instead of busting your eardrums with Metallica at top volume to drown out the world, you can preserve your ears and listen at a healthy volume and STILL drown out the world.
BTW - if you have a crappy stereo in your car, DO NOT drive with these on. You'll have no chance of hearing the po-po when they pull you over for dancing like a teenage girl when you jamm to Xtina.

Etymotic makes some of the best earbuds around. Comfortable, well-built, sound awesome. The only thing better is Ultimate Ears.

keep your lugholes clean and full of BASSSSSS

These are truly awesome earphones. They effectively block out background sound w/out forcing you to blast out your eardrums. The sound quality is very clear w/surprisingly good bass for such tiny speakers (I listen to a lot of electronica w/pounding beats so good bass is essential for me). Handles more delicate classical music well too.

Also, they are super-comfortable and lightweight- ideal for endurofest rides and runus. The extralong cord is nice but can get tangled a bit too easily (via grenadefishing)

my ipod earphones fall out when I run (via joe)

Great head phones. The only set yet I wasn't able to blow up!

I have a pair of Etymotic Isolator 6i headphones. I had to buy the supplementary foam earpieces for people with pathologically small ear canals.

I found the sound quality surprisingly good once I finally got them inserted all the way so there was no air gap around the edges. Hard to believe sound (including bass) so good can come from such a small package. Clipping the wire to my shirt prevents it from making loud wire-attached-to-a-tin-can sounds every time I turn my head.

If earplugs agitate you -- like make your ear canals itchy or anything -- then these headphones may do the same. It's just like wearing earplugs.