I have a 30 Gig iPod Classic, purchased in December of 2006. Last week, a couple months shy of 3 years later, the iPod output went dead. No sound came out of the headphones, but everything else worked properly. Resetting and reformatting did nothing.
I found this link on MACNN that tells you Apple is aware of the problem. If you press on the lower right hand corner, you can momentarily get the sound back. It is a manufacturing defect. Call 1-800-275-2273 and let the tech know that Apple is aware of this, that if you press the lower left corner, sound comes back, they will forward you to a product specialist. That is of course, if this is true for you. I had to press and fiddle for a few minutes, and got a few seconds of audio.
Don't put your iPod in the freezer because this will cause condensation, which may produce water damage. When Apple asks you return the device, they will look for water damage as well. I just called, followed the procedure, and they said it will be repaired or replaced. Chances are, it will be replaced because they said I may have to wait an extra day for the custom engraving. If they were going to fix it, the engraving wouldn't change.
I would have posted a thank you and reply on MacNN, but the site has this impossible registration process that either tells me I cant use my name, or I have typed in the wrong captcha letters. After 2 or 3 attempts, I really didn't care anymore. Sorry MacNN, your registration sucks.