Ive found an excellent media player called "totem". It Plays all the popular streaming media from the net (audio & video) and plays dvd's etc.
I dont know if it works in gentoox but ive just had it running perfectly in xebian so as long as its in the portage tree it should be just as effective.
At last an alternative to using windows media player on the PC and you can now watch streaming video/audio & internet radio on the xbox..