I find it amusing how Christian says they moved away from "their" ESD to a standard PulseAudio. ESD was the Enlightenment Sound Daemon (though it may have been maintained by GNOME hackers at the end), and PulseAudio is only "standard" insofar as it was included by default with most distros (i.e. ESD or aRts would have been "standard" under that definition).
KDE at least supports PulseAudio better than ESD but it could as easily have supported ESD if it were necessary, especially if there was as much support from ESD devs as was provided by PulseAudio devs (ESD was already in its nadir before KDE 4.0 thanks to broad usage of gstreamer making ESD redundant for most audio needs).
PulseAudio is used by almost all distributions and GNOME settled on it. ESD was not used by all distributions, furthermore it had bugs and wasn't maintained.
KDE at least supports PulseAudio better than ESD but it could as easily have supported ESD if it were necessary, especially if there was as much support from ESD devs as was provided by PulseAudio devs (ESD was already in its nadir before KDE 4.0 thanks to broad usage of gstreamer making ESD redundant for most audio needs).