The new audio control is much easier and cleaner then the last one, and you can now change the volume of individual programs as well.
Let's face it, with ALSA, PulseAudio and JACK all available options in a typical Linux installation, open-source audio is a bit of a mess. If this new interface in Ubuntu Karmic doesn't simplify things it at least makes it easier to get at and use the more advanced features.
This revelation is but one in a list of 10 favourite new things in Ubuntu 9.10 -- others include Ubuntu One, the free cloud-based storage service and the previously mentioned Ubuntu Software Center. Click through and have a look!