1. FF7; This one's a classic for a reason. I used to place it below FF9, but after some replays it's just better. Everything comes together perfectly for this one.
2. FF9; One of the most underrated games of all time, probably. The story was great, I loved the battle system, and I loved the return to the old school FF feel. Zidane is the best protagonist of the series, and Kuja is probably my favorite villain of the series, too.
3. FF8; This is the first one I played and I think that nostalgia takes over any flaws it might have. Even just a snippet of the music can bring me back. I still love and defend the junction system against anyone that hates it.
4. FF6; Another classic game. There's no real flaws here, it just doesn't hit me with nostalgia as much as the others. And I think the cast being bigger than the top games makes it a bit harder to connect with them all, but still it's a wonderful game.
5. FF10; This has a superb cast and a good fast paced battle system. The world was well thought out, and the story was intriguing throughout. The first time voices were in an FF worked wonderfully and added a ton of personality to the entire cast. I think this one was a bit linear for my taste, and I missed the world map, but I still loved it.
6. FF11; I spent so much time on this game it isn't even funny. It had its flaws, but man was it addicting. And the world was just so huge and had so much to explore. Nothing tops the first days of exploration I had on here. I felt like a pioneer charting dangerous territory. You never knew whether where you were going was going to get you killed or not in the beginning, and I loved that.
7. FF5; The best job system in the series. Supremely fun to play and plan out. And the music was great.
8. FF4; I loved the cast and the music, as always. The plot twists were great for its time, as was the story.
9. FF12; This one could literally be my number 1 game if it had been what Matsuno planned. I think it'd be my number 1 of all time if it had been that. Sadly, it wasn't. It was missing a lot, especially around the middle. But despite that what we did get was really great. The battle system felt fresh and felt like the direction the series should really take. And I had some exhilarating hunt battles since I took some of them on way earlier than when I should.
10. FF13; I really don't get the hate this one gets. Sure it's lower on my list, but I still absolutely loved it. The battle system was refreshing and modern, and I loved how the cast of characters fought with each other. That was also a refreshing change up. The only reason it's down this far is because they hold you back a bit too much for a bit too long.
11. FF2; I think this one doesn't get enough credit. I like the idea behind the battle system, and the story is really great for its time. FF4 gets more credit with adding the typical FF story, but here's where it really happened.
12. FF13-2; This couldn't quite hit where FF13 hit. It was a sufficient game, and fixed some things like the linearity, but it did drop the ball with difficulty curve and the wacky time traveling storyline.
13. FF1; It's a great game and a great start, but by now it's just a bit old and dated.
14. FF3; Again, this is a great game for its time, but by now it's dated a bit. And I think it loses out for me because FF5 perfected the job system.
15. FF10-2; This is the only one on this list I couldn't beat. The battle system was great, but I couldn't take anything even remotely seriously. And the story seemed like it was barely even held together. Someday I'll give this another chance....
My real number 1, though, is Final Fantasy Tactics. That beats all the rest hands down in gameplay and story. Really, it's one of my favorite games of all time.