Cons:Size adjustment tabs are fairly loose and cheaply made; In-cord volume would have been nice
The Bottom Line: These headphones provide more than enough quality for the average audiophile at a much lower price than the competition.
When a professional A/V technician bought a co-worker of mine some Koss R 80 headphones, I took that as a pretty strong endorsement. For about $30, these headphones have more than enough sound for the casual audiophile.
These closed-ear phones are quite comfortable. Some complain that they cause their ears to sweat, but I haven't noticed that. The sound quality is excellent. You can plug them right into your sound card output, but the sound is greatly improved with the amplification provided when you plug them into powered speakers. The headphones deliver a decent amount of bass, and have a crisp upper range.
The construction of the headphones is fairly nice for $30 headphones. The cord is an ample 8 feet, coiled. It plugs into the left phone, using a connector similar to that of a telephone cord (so if you do disconnect the cord from the phones, which I don't recommend, make sure not to break off that little flange). If the cord does become damaged, though, you just have to replace the cord, and not the headphones (honestly, I don't know how much you'd save doing that, though). The one complaint that I have is that the size adjustment tabs at either end of the headband are fairly loose, and don't look or feel like they'd stand up to much wear over time.
Still, these headphones feel good and sound good, and cost a heck of a lot less than comparable phones from other brands.