I would say that they are definately worth playing, 9 is quite good, has a few memorable scenes, good story, good ability system and diverse characters. 8 was good, but i didnt enjoy it as much as 7 or 9.
LOL, i felt the characters in 8 were too mature, but intruiging.
Watch the FF7 PS3 technical demo here.
http://uk.gamespot.com/ps3/rpg/final...vii/media.html