banshee-0.10.6 includes the following dependencies on gst*-0.8.11: =media-libs/gstreamer-0.8.11 =media-libs/gst-plugins-0.8.11 =media-plugins/gst-plugins-gnomevfs-0.8.11 mad? ( =media-plugins/gst-plugins-mad-0.8.11 ) vorbis? ( =media-plugins/gst-plugins-ogg-0.8.11 =media-plugins/gst-plugins-vorbis-0.8.11 ) flac? ( =media-plugins/gst-plugins-flac-0.8.11 ) aac? ( =media-plugins/gst-plugins-faad-0.8.11 =media-plugins/gst-plugins-cdparanoia-0.8.11 Some of these, including gstreamer, gst-plugins and gst-plugins-flac, are now at 0.8.12. Because of these dependencies, after installing gst-*-0.8.12 I get the upgrade/downgrade shuffle for the gstreamer 0.8.12 packages. Banshee needs to be tested with 0.8.12 dependencies allowed so that this doesn't happen.
Also see bug 123838 for similar dependency problems between gst-plugins packages.
This is already fixed: http://sources.gentoo.org/viewcvs.py/gentoo-x86/media-sound/banshee/banshee-0.10.6.ebuild?r1=1.3&r2=1.4