For rhythmbox-0.8.0 to work with ogg files you need gst-plugins-vorbis and gst-plugins-ogg. Currently the ebuild will only look for gst-plugins-vorbis. See #48282
the reporter is correct this is one of the problems with the 0.8 ebuild eradictor... please fix. I wonder why this didn't get fixed immediately in bug #48282 ?
fixed in cvs. thanks.