Following to an issue with esound not playing GNOME system sounds, I have decided to give Pulseaudio a try.

Installing the pulseaudio package pulled all necessary dependencies, including the esound compatibility plugin. I have added local users to the pulse-rt group, as recommended. After this, all worked perfectly except the main channel was muted and its volume set to 0% after rebooting.

I have found that not loading the module-device-restore does fix this issue, strangely. If you encounter the same problem, try and comment out the line load-module module-device-restore in /etc/pulse/default.pa.