My favorites:
1. Final Fantasy IX
2. Final Fantasy X
3. Final Fantasy XII
4. Final Fantasy IV
5. Final Fantasy X-2
6. Final Fantasy VIII
7. Final Fantasy XI
8. Final Fantasy VII
9. Final Fantasy II
10. Final Fantasy VI
11. Final Fantasy I
12. Final Fantasy V
13. Final Fantasy III
This list changes for me as I play and replay them. 4 shot up when I beat the DS remake. I already know FF13 will break the top 5 due to battle system alone.