By the way, I have another app recommendation for everyone, and I wasn't sure if it was mentioned already:

Tasker

There are other apps that do similar things, like Locale. It basically gives you an incredible amount of condition-based control over the phone. The simplest example is that I can set my phone to go into silent mode at a certain time each evening and go out of it again in the morning. From there it gets really insane, really fast. This article did a better job of explaining everything it can do than I could.

*edit*
Example: I have the Nexus One dock and I keep it on my night stand. I created a profile that puts the phone on silent mode specifically when it's placed on the dock. That way it won't trigger when/if I plug it into a power chord anywhere else. I friggin' love this app. It's not free, but I think it's worth it.