Panasonic RP-HJE120-K In-Ear Earbud Ergo-Fit Headphone (Black)

They just work. Nice, clear & flat-sounding (nothing in audio spectrum particularly stands out -  a good thing, if you want to approach "analytical", which these things most assuredly are not).  Listening to 320 kbps ambient tracks on internet-radio.com right now.  Very immersive, good sound stage / separation.
 
Very Comfy fit, using large silicone tips. No cable noise. Decent build quality.
 
Excellent bargain at Amazon.com - $9.45 USD.  What's not to like?
 
These things garner 4.4 out of 5 stars among 38,316 reviews on Amazon.com, which has to count for something, I would think. I agree; I'm giving these 4.5 stars.

They sound better than anything I've heard at this price point. I use these earbuds with my iPod Nano every day. The one thing that makes these things annoying as crap is the stupid cable that gets tangled and stays tangled. 
 
They isolate noise OK. My ears aren't the best shape for them so if I wiggle my ears sound suddenly leaks through. I replaced the rubber eartips with the ones from JVC Marshmallows - in my opinion the most comfy tips for buds. They make the driver a bit more distant from your ear but this is solved by raising the volume.
 
Separation is poor which is to be expected. Nothing like my HD518s and I don't expect them to be.
 
Honestly, for 6 bucks these are great. I've never owned any really great earbuds but I do know that I normally tear through earbuds because I am not nice to them and none have lasted as long as these have. I got these right before the 2014 year ran out and, seeing as it is currently September you could say that these things are build pretty well.

Originally purchased as temporary replacements. I've had the same pair for something like 5 years now-  they've gone on to see a lot of gym and work use, and are so comfortable and secure that I've often used instead of inears with much better SQ. Don't get a lot of rotation lately, but the 120s live on as the backups I keep in my bag.

The sound isn't quite good, but surprisingly decent given the price (boomy bass, ok mids and treble missing some detail, narrow and slightly soupy/muffled sound common to the budget cohort but not distractingly so). Isolation is ok for mild city noise, until a truck drives by. Construction isn't remarkable but the shells and plug seem solid, and earns a lot of credit considering they've lasted me longer than every other headphone I've owned in spite of seeing a lot of rough use- the one gripe is a thin, tangle prone cord.

Price and comfort are what make the HJE120s worthwhile, for budget listeners, as a cheapo backup or temporary stopgap, and comfortable beater/utility/podcast set for those who don't mind occasionally compromising  on SQ.