I blogged this before, the ringer on/off switch on my iPhone fell off soon after I bought the phone (yes, on launch day). Last week, the audio jack broke as well. The mic-input is not working anymore. This is a problem for me as I use a wired headset all the time with the phone to listen to music and to make calls. Of course, one quick schedule and visit to the Genius bar, and I have a new replacement phone. The only quirk that I ran into is that when I restore my phone from backup, it did not restore everything. Specifically:

I have to re-enter all my email account passwords
I have to re-arrange all my apps on the screen pages

One additional observation that I have is the new ringer on/off switch feels different from my old one. It is much looser and snap into position quicker. The old on was much stiffer -- and I wonder if that's the reason why it broke so easily.