LCD is definitely the best option right now. LED is just waaaay too expensive so far. In terms of brands, stick with Samsung, LG, Sony, or Panasonic. I personally am a fan of the Samsung's these days, but I got to play around with a 52" Sony recently and the on screen menus as well as the ability to mix/match audio and video inputs was pretty crazy! 120Hz is definitely the way to go (240Hz can't even be seen by the human eye) and of course 1080P for anything over 37".
If you have any questions, just PM me! I know pretty much anything you'd probably want to know about them!