Boxee might get all the attention but Plex is without a doubt one of our favorite Mac media center apps. So it's with wide-eyed interest that we tell you about the Plex client making its first tentative steps onto the second generation Apple TV platform. Naturally, Cupertino's not behind the initiative to replace Apple's own "Lowtide" 10-foot user interface -- this work is being done by the Apple TV jailbreak community. The ATV2 build is still just a proof of concept so it's buggy and limited to video playback (no music, i