[Cynicyclonian]

In my definition, healthy headphone is one which doesn't hurt.  And I've seen a pattern that the more noise-cancelling a head-phone is, the more it hurts my ears.
 
Bottom line, to narrow down the choices, I am going for a sport headphone and I simply couldn't locate one. 
 
Please let me know your output.

 

[sari0n]

Meelectronic M6's are the most common choice fore cheap sport headphones.  They're also the most comfortable ones I've ever used.  They come with tons of tips that you can try if they hurt you ears.  If even those are too uncomfortable for you, you might just want to pick up one of those earbuds with hooks at a local best buy or something.

 

[Cynicyclonian]

They aren't breathable.  
 
My budget: $150.

 

[sari0n]

By breathable you mean no silicone tips?
I would take a look at some of the Sennheiser earbuds then, they make quite a few that should stay on pretty securely with earhooks.  There are also some twist to fit models but I find them to be pretty uncomfortable.

 

[Cynicyclonian]

By breathable I meant something that doesn't have noise-cancellation effect.  The only headphone I have found that does that is my brother's Denon AH-D7000.  So when I yawn..the air is released instead of being trapped inside.

 

[Smallville]

So you basically want a pair of headphones that doesn't block out sound. Then, any pair of open headphones would work. If you want it for sports, check out the Koss Portapro or the KSC75s
 

 

[Cynicyclonian]

I have already tried KSC75s and was very pleased with them.  So think I'll try the other one you recommended.  Thanks!

 

[swbf2cheater]

A very comfortable headphone that does not isolate? Hmm...
 
Nothing small that I am aware of is even half decent that fits your requirements, you might be stuck with full size sets.  If that is the case, well then welcome to head fi and there are hundreds of great open back sets.  The best and cheapest open back set that I can think of happens to be one of my favorite sets, which is the Sennheiser HD485.  It is on the small end of full size sets, allows for easy cable swapping ( any standard 3.5mm cable should be fine, if not, then Griffin makes a great cable that I use that fits it that I can show you, its like $10 bucks ) Its a bit clampy, but not as much as some of the other sennheisers, its fun to listen to, light and pretty cheap on ebay sometimes, I see them for 20-40 now and then.
 
There is also the Sennheiser HD238 or PX100-ii or PX200.  both are great
best of luck
 
-cheater

 

[JxK]

For sporty headphones that don't isolate and are supremely comfortable, I heartily recommend the sennheiser px100. I've tried both the older model and the new px100-ii and recommend the original version. Sound quality is virtually the same between the two. The px100-ii has better build quality (not that the original is poorly built by any means), but it sacrifices some comfort for it. And it's considerably more expensive.

 

[FearSC549]

Supra aural headphones such as KSC75, PortaPro, SportaPro(I believe they use KSC75 drivers), PX100, PX200.