pulseaudio depends on eselect-esd. eselect-esd blocks esound. This means that in order to install pulseaudio you have to clobber anything that depends on esound, including gnome. pulseaudio is supposed to be a drop-in replacement for esd, but you can only install it if you wipe most of the stuff that might have used it off your system, in the process making your desktop unusable.
emerge -C \<media-sound/esound-0.2.36-r2 *** This bug has been marked as a duplicate of 79606 ***
*** Bug 152892 has been marked as a duplicate of this bug. ***
*** Bug 153117 has been marked as a duplicate of this bug. ***
*** Bug 153129 has been marked as a duplicate of this bug. ***
*** Bug 156241 has been marked as a duplicate of this bug. ***