What are you mainly going to watching. If you are into video games, sports, and have a blu-ray player, i'd go for the 240hz. If you are just going to watch a random show here and there, it's not worth it. Honestly, I can not really tell the difference, but I wasn't really blessed with great eyesight. LED vs LCD the greatest advantage is LED will give you better light uniformity in specific areas. light uniformity has been an issue with LCDs since their inception. without going into great detail is that it'll produce an overall sharper picture, especially in dark lit scenes. Blacks will be black, not some charcoal grey on your screen. this is product of having hundreds of light sources instead of one. to make your decision even tougher, there are two technologies for LEDs now. local dimming sets and edge-lit sets, with local dimming being more expensive. you can achieve darker darks with local dimming sets. more $$ though. basic article on gizmodo
Samsung vs. Sony I can't provide any tangible comparison, but I would get a samsung. I have experienced great things with all samsung devices in the last few years. i have a DLP and LCD from them. my grandparents and parents have bought samsung TVs and we have had no problems at all. what it really boils down to you is determining what you are going to watch.