I've been playing with sound for some time now and I never really got it the way I liked it. Sometimes gaim would cache its sounds until I stopped xmms because /dev/dsp was in use. In other words there was no hardware nor any software mixing. At first sounddaemons tried to solve that issue, but nowadays there is more elegant solution to solve all this. Have a look at how you can have all of theat fixed on Gentoo :http://gentoo-wiki.com/HOWTO_ALSA_sound_mixer_aka_dmix