I still haven't beaten the stupid fucking Mexico mission in R6, so I'm a lil' underwhelmed. The faces are kinda gross.
Gears of War looks fantastic, plays even better.
Viva Pinata looks wonderful in HD, all the colors really come to life, nice sharp edges on all the animated menus and whatnot. Have't tried, JC, Dead Rising or GRAW yet. Keep meaning to pop in Oblivion.