I am really new to audio and am just trying to obtain a very high level
understanding of what audio specs mean. I have been trying the web and
using Google Web and Group search. At this point I just feel overwhelmed.

I am trying educate myself to buy two things. The first is headphones for
my iPod. Could someone explain the various specs (sensitivity, impedance,
response accuracy, noise reduction, etc.) at a very high level? The other
thing I need to do is replace my home audio system. The speakers are still
good, but I need a new receiver. Could someone explain ohms rating on the
speaker and what you need to be aware of when buying a receiver (this is a
home theater system).