A few months ago, I upgraded the firmware on my venerable Airport Extreme to 5.7.

After the upgrade, the Airport regularly gave me fits. At least twice a week I had to cold boot it. My first thought was "there must be something wrong with my Airport Extreme" and I was close to replacing it.

Being the cheapskate that I am, I looked for alternatives first, and saw someone mention that going back to Airport Extreme firmware 5.5.1 had resolved a similar problem.

So, I downloaded and installed Airport Extreme firmware 5.5.1, and it worked! I haven't had to touch my Airport Extreme since.