Currently rhythmbox ebuilds require gst-plugins-cdparanoia to play audio cds and enforce the dependency using the element ">=media-plugins/gst-plugins-cdparanoia-0.10". However, rhythmbox can also play audio cds using the alternative plugin gst-plugins-cdio, who use the more actively developed libcdio library. The dependency should be changed in something like "|| ( >=media-plugins/gst-plugins-cdparanoia-0.10 >=media-plugins/gst-plugins-cdio-0.10 )".
Actually, this is not limited to rhythmbox. sound-juicer can also use cdio. I haven't gnome-cd or banshee, but I'd bet they could manage too.
They all work with gst-plugins-cdio, and they're all fixed (except gnome-cd, which didn't seem to have a dep...)