If you look at the prices below in the link as an example renting is quite expensive 18 months worth of rental woud mean you had effectively bought the set, so if you bought a set in the first place and even adding a 5 year warranty you would be quids in over 5 years ,one reason why i would never rent a tv set from anybody.
http://www.forbesdirect.tv/List08.asp?Group=LCD42