Plasma screen has a burn-in problem, i.e. the long period of dispaly of the same image will burn image on the screen.
So, if you use long period, your window desktop will permantly burn to the Plasma screen.
LCD is fine. You can get a nice 32" LCD TV for about £1000.
Nothing is future proof. Only sky provide HDTV in Europe at the moment, so extra cost to get a so-called "HDTV" ready screen is not necessarily a good idea.