What do those numbers mean on a headphones package?

Question

Things like impedance and ohms - what should I look for? What numbers are ideal?

Answer 1

Check this excellent review in Wikipedia

http://en.wikipedia.org/wiki/Headphone

usually you want a High Frequency response - supporting as low frequencies as possible, say 10 Hz (for good base sound) and as high frequencies as possible (say 15 kHz or higher)