i would recommend HDMI over composite cables. composite cable are well capable of transmitting 720p, and over long distances. but for some reason on my plasma tv, when i use composite, i can notice horizontal thin lines on black background, something like noise. i tried different cables but the same result. over hdmi the black is dark clear black with no noise. the only disadvantage of hdmi is not all audio is streamed, but that is not problem for me as i use L/R stereo cable for my speakers anyway.
i noticed that if i have both composite and hdmi connected to device, it streams over composite first, and dont stream anything over hdmi. so if u want to use hdmi, unplug the composite cables not to create confussion