About the FFs, I've been playing the 7th, 8th and 9th. The 8th seemed quite complex to me at first with the junction system but I ended to handle it.
In the 9th I had Freya as favorite character, especially for the spears, my favorite weapon (whatever the game is); and in the 7th didn't really mind the weapons as long as I focused more on materias. Then I had some critics (both good and less good) between 7 and 9 :
-true Materia is a very good system because you can affect magic, chimeras and abilities to whoever you want ; though this system had some defects, like the All materia and chimeras allowing the multiple-enemies and use just several times (despite in the 9 you can multiple-target enemies without special abilities and summon an unlimited number of times)
-in the 9 this is the reverse, each one has his own skills and you often have characters split (in the 7th it's easier to choose the characters you want to, they are rarely split in groups) and it is slower to level up all abilities, what I liked was levelling up all my characters on an equal base, having them at more or less same level, that is much easier in the 7th in my opinion
-I found the map system better in the 9th, you could see which town corresponded to which point
-about the chocobos it's harder to see because each one has a proper sidequest, but I admit I preferred the chocobos races rather than chocographs (even if I thought diggin quite entertaining)
-I also think it's much easier to gain money in the 7th than in the 9th
Then about the movies I only saw Advent Children, not in complete version, but yet what I liked most was the great improve of graphics, if I compare to the game, then the plot was quite interesting though I was disappointed on the ending, found it too easy