Tie between X and XIII.
And I expect XVI to be a good to great game and to still be considered trash by lots of boneheads in the fanbase.

Bolded: *Checks oracle from the future* ... Yep, seems about right.

IX is my favorite, such an amazing game.

The one with the sphere grid, that gave the random encounters meaning, otherwise I find random encounters very annoying, especially when you don't know where you are supposed to go next and walk back and forth.

Excluding VIII is a joke. It's one of the best entries of the series. I'm sure it would have got as many votes as IX.

The fact "Other" only has 9 votes makes this claim very unlikely. Although, I would have given XV's place to VIII in the poll.

Hard to decide between VI and IX. I chose VI because of Kefka and it was my first Final Fantasy game, but its close.

Final Fantasy 7 is my favorite.  I've been a huge fan since the very first game though.  Here is my experience with the series.

Final Fantasy 1 - This was the NES RPG that felt the most like D&D.  I loved it!  Most people ignore this series on the NES, but if you asked me what my top 3 NES games were at the end of 1990, I would have said Zelda 1, Ultima 4 and Final Fantasy.
Final Fantasy 4 - Mind blown!  This game had a huge intricate narrative that I had never encountered before in a video game.  It also had new character classes like Dark Knight, Summoner and Dragoon.  I personally thought Dragoons were totally badass.

Final Fantasy 6 - My SNES was stolen about a year or so after I bought it, so I never got to own FF6.  I visited my half-brother (in another state) once, and we rented FF6.  I got a little ways past the Opera House and assumed that I had seen most of the game.  (Spoiler: I was wrong.)  A few years ago I played this game all of the way through for the first time.  It's an awesome game from beginning to end, and I wish that I had gotten to complete it when it was a current title.
Final Fantasy 2,3,5 - I've played these, and they are fun, but I probably would have enjoyed them more when they were current titles. 

Final Fantasy 7 - For a long time, I considered this my favorite game ever (not just favorite FF, but favorite game period).  It has my favorite story and favorite cast.  It has my favorite soundtrack of any game.  The materia system is my 2nd favorite class/leveling system (with the job system being #1).  Back in the day the FMV graphics blew me away.  I'm currently playing through this game again right now, and while the graphics are dated, the rest of the game is still an awesome experience.
Final Fantasy 8 - A disappointment.  I like the story and characters, but the battle/leveling system really sucks.  The card game is fun though.

Final Fantasy 9 - Once I played this, all mistakes from FF8 were quickly forgiven.  This game is another masterpiece.  I feel sorry for all of the people who rushed to the PS2 and missed playing FF9.
Final Fantasy 10 - Another great experience.  This is the first fully voice acted game that I'd ever played.  This also illustrates how Final Fantasy games used to really push the boundaries of a consoles new capabilities.  Whenever, I wanted a groundbreaking experience on a new console, the game I would think of is Final Fantasy.  Final Fantasy 1, 4, 7, and 10 were all groundbreaking games.  They all really showed off the capabilities of the hardware they were on (and not just with graphics either).

Final Fantasy 11 - This was the only game I played for about 2 years straight.  Basically from NA launch to FF12's release I only played FF11.  I had tried several MMOs before this, but this way easily my favorite.  After FF12 came out, I realized that I gradually wanted to get back into console gaming.
Final Fantasy 12 - This story rips off Star Wars far too much for my taste.  In spite of all that, the gameplay is great and I thoroughly enjoyed myself for about 100 hours with this game.

Final Fantasy 13 - Here it is, the beginning of the end.  I bought this game day 1 and played the hell out of it just like I did with every previous Final Fantasy game since FF7.  I bought a PS3 and HD TV beforehand in preparation for FF13.  This game was such a huge disappointment.  The first 20-25 hours are total shit.  After that, the gameplay actually becomes extremely good.  I went on to play this game for about 100 hours total and I was left wanting more.  And yet, I cannot forget that the first 20-25 hours are total shit.  FF13 marks the beginning of this series "fun but disappointing" phase.  This game was fun, but also really disappointing.  FF13-2 and Lightning Returns were also fun but disappointing games.  Final Fantasy used to be my favorite series and it wasn't even a contest.  This trilogy is where it stopped being my favorite series.

Final Fantasy 14 - Haven't played it, but I want to say the original release was another huge stain on Final Fantasy's record for me.  This series was not what it used to be and neither was Square-Enix.  From what I understand, the game is now extremely good.  I kind of want to play it, but I also like playing a variety of games.  I think if I get into FF14, I will probably stop playing other games for a while like I did with FF11.
Final Fantasy 15 - I got this game a year or two after release.  I played it for about 1-2 hours and then just quit and never went back to it.  This is not a Final Fantasy game.  I no longer have the endurance to push onward like I did with FF13.  I bet it will be a fun, but disappointing experience if I played it, but...I just can't.

Final Fantasy 7 Remake - This game is fun, but disappointing.  That's the type of Final Fantasy games they make now.  It's definitely fun, and yet I am extremely disappointed at the same time.

What are my expectations for Final Fantasy 16?  Fun, but disappointing.  That's the kind of games they make now.  I'll enjoy myself while also being really irritated or frustrated with parts of the game.  What would I like from FF16?  I'd like them to bring back Sakaguchi.  That is the short answer.  A longer answer would be that they decide cutting edge graphics are not important.  Instead they make a game with an awesome story and fun, but relatable characters.  They make a huge world to explore like the FF6-9 games, and the game starts somewhat linear but gradually becomes an open world game where you can explore everything with an airship at the end.  It needs to be party focused, and ideally turn-based, but a combat system like FF7 Remake would be good too.  The graphics are not really what make a Final Fantasy game great.  It's the story, game world, characters and the feeling of being on an epic journey.  (Kickass music is also a must, but they are still pretty good with that.)

Since I haven't played them all I don't find myself qualified to vote yet. I've only beaten 7 and 9. Of those two, 7 is the better one. I'm a good chunk into 8 and don't like it lol. I also have been told Bravely Default 1 is essentially a FF game and I'm probably 1/2 to 2/3 it on my 3ds and so far I like even more than FF7.

Ah look, the twice yearly thread of What's your favorite FF game.