I've completed every single one other than III(which is a work in progress) and this is what I can say

1) FFVII
2) FFIX
3) FFIV
4= FFV
4= FFVI
6) FFII
7) FFX
8) FFI
9) FFIII
10) FFVIII

BUT if FFX-2 and XI were to be included, from my estimations I think I will like FFX-2 pretty similar as I did to X, and XI is EVIL! because MMORPGs are HELLSPAWN!!!!!!!! But it'll still be better than 8.