Whenever I startup Audacity, it apparently mutes my input mic. This can be seen in the Sound preferences application: I can launch Sound, go to the Input tab, observe that the mic is not muted, and then, while Audacity is launching, the mute button magically becomes checked. By unchecking it, I can then record sounds as usual, but I would prefer not to have to open the Sound application each time I want to use Audacity.
This problem was present in 11.04 and continues in 11.10.