For larger screen sizes Plasma is the better technology, with LCD being better for smaller sizes, although it is improving all the time.
However, until OLED become widely available (its supply is being deliberately limited by the panel manufacturers to milk production ££££ of LCD & Plasma) then personally I would go for LCD/LED technology at the moment.
What are being maketed as LED TVs are actually LCD with LED backlighting - or LCD/LED for short.
However, it really depends on what you want - picture quality or price. If the former then LCD/LED is the way to go, if the later then (personally) plasma would be the choice.
In either case, make sure that you get plenty of HDMI interfaces on the back. I've got a LG plasma and am delighted with it, shop around and you can get an LG42" plasma for about £500. A 5 year warranty will increase the price somewhat - although in saying that Richers offer good prices and very good value 5 year warranty.
HTH ....... Rob