I am asking the same question but for my SOny V2000. I used to have intermediate for VGA but its too black via hdmi so i have gone for standard. Not as bright but not as dark. Dunno if its right or not lol
With my TV, standard gives the best results. Tested using a grab of the SkyHD test card, played as a 1920x1080 video through the XB360 media player. This gives (almost?) identical results to playing the original test card on SkyHD.