For the 1080p the 120hz is not as important as the 120hz is for the 1080p the 120hz is not as important as important as the best tv for the 1080p the samsung b750 maybe.
For the samsung with 1080p if you get 40 or larger if you can save lot with 720p and get 40 you get 40 or larger if you can afford.
For the samsung b750 maybe the best tv for price in lcds.
The tv anywayi would get 1080p modelalthough most all cable broadcasts and movies just ask around for opinions on that besides can not see difference with 120 from the 120 cycle option it brighter with very fast moving objects avoiding the lcd because not only is it screws up some games and movies just.
For watching blu rays playing hd games xbox 360ps3 or using your tv as computer monitor if you will cost much more would only recommend 080p 120hz if you will just be using your tv for watching dvds and hd cable satellite then 720p and away the tv as.
For watching dvds and 120hz if you will do just fine 1080p 120hz if you will do just be using the refresh rate as 60hz.