I played all FF's, apart from FF11 & FF14, but i have not finished FF2-5, so wont mention them.
1.FFX (first one i played, best story IMO)
6. FF tactics advance
7. FF12 (mediocre story, ok game play which sometimes plays itself if you do gambit system right)
8. FFX-2 (bad story, good game play)
9. FF1 (GBA)
10. FF13 (not a true FF game, bad story, bad non-strategic gameplay that plays itself, bad characters)