i am so lost when it comes to external displays, even though i would really like to buy one to complement my 13 incher macbook. with the resolutions, the HD, the compatibility...AHH like, whats the difference b/t hooking it up to a 720p HDTV vs. a monitor which is 1920-1200? is there an intoduction/faq guide i can find somewhere? AHH!!