what to look for in LCD TVs

i am looking to buy a new TV. with plasmas and LCDs out on the market i have been thinking it over and i think i will go with LCD over plasma. but for something that will be able to keep around for a while i need to know what is the MAIN things i need to look for. i assume built-in HD tuner and also assume it compatible to ATSC, NTSC. now Clear QAM, Integrated QAM, or just QAM i dont know the difference. i live in the USA so i am not sure what new standards are out or coming out. but any infomation to clear up alot of question about things to look for in a LCD, may it be todays standards or for tomarrows standards. any help would be great.