New entry in this category:
I was shopping at Ross (a discount close-out clothing and etc. store) the other day and I saw these open type (foam ear pieces that rest against your ears, not covering them) headphones for $5. They are JVC's and they have an in-line volume control and are foldable as well.
Well, I expected I'd end up throwing them away, but guess what? They sound GREAT! A bit of research revealed that they sold for up to $25 but were discontinued for whatever reason. These sound really really good - good bass, good treble, good midrange, and are great for just everyday knocking around town use. I bought 2 so I can have spare when these break.
The one drawback is that they seem to be made rather flimsy and may well break if you're not careful. But for $5... I bought the last 2 there, and if I see more I'll buy a couple more!
These sound at least as good as any other portable headphones I've tried, some, like the Koss that I paid $20 for don't sound nearly this good.