Gold membership gets DLC a week before silver and also with gold you can play multiplayer, silver you can only private chat with one person (gold up to 8 at a time) and no online play. your 360 will come with 3 one month trials of gold (1 for each gamertag you make up to 3)
yes all newer 360s have a lesser failure rate but its still a possibility, you have a 1 year warrenty for everything and a 3 year for jsut the RROD
and you are right on the elite, and of course the elite is black. the pro comes HDMI compatible but doesnt include the cord. i beleive one is like 50 dollars (US). the memory is a bit extreme, i mean its better than the old 20gb pro but they just upgraded that one to a 60 so that should be your choice if you dont want the black console and HDMI cord.