I just wanted to add that having experienced the same problem just two weeks ago, when I went to the Genius Bar and after they acknowledged the problem, I was offered a replacement which consisted in paying $169 for a refurbished unit !!! The broken unit was 27 months old !! I proceeded to call a supervisor and explained to him two things:
1) $169 is the cost of a refurbished unit from Apple straight out of Amazon.com. Since they had no replacements in the store and they would have to order it and ship it to me, what is the point of Apple's Tech support making me go to the store and spend a total of two hours just to offer me what I could have done from the comfort of my home?
2) It is the first time in my life a WiFi router fails on me. These products get replaced because they become obsolete in one way or another. Not because they die off.This is true for all brands. I admonished the manager about the sorry state of their brand perception on the street: Apple Products either die prematurely or they are killed prematurely by Apple itself. This appears to be its revenue re-generation model. Not good at all for the brand.
In the end, they offered me a new one for $50, offer which I shouldn't have accepted having been hustled and betrayed by my brand, but it was 9pm, I need to get back home and I didn't want to leave my home without WiFi while away on a business trip the they after for a week.
Finally, after years in the industry, it amazes me how someone gets away at the product design stage with sticking a fan to solve a poor heat dissipation design problem. Once you put any kind of fan in a product like this, its MTF accelerates tremendously. All because the design team didn't want to use more robust and conventional cooling techniques. It goes to prove: there are people who would rather loose the point rather than looking bad with the racket on the tennis court !!