1. FFVII
2. FFIV
3. FFIX
4. FFX
5. FFVI (I just didn't like this one as much as some people).
6. FFVIII
7. FFI

I have yet to play XII (next game on my list actually), but from what I have seen it looks pretty good. Ten would be higher if I didn't hate the characters in the game, because it is actually a really solid game.

I'll only list ones that I have played recently, I need to go back and play some older ones to judge them again:

1. FFX
2. FF XII
3. FF X-2
4. FF XI

I plan on playing FF III, V and VI on the DS and GBA soon and I and II on the PSP some time in the next few months.

IV, VI, VII, and VIII, in that order. Final Fantasy IV is one of my favorite games ever, in any genre.

Haven't played I, II, III (I just got the DS version, though), V, and any of the games above VIII.

Ones I've beaten recently enough to be able to gauge,

FFVI
FFX
FFVII
FFXII

I'm having trouble really deciding between X and VII, so maybe a tie there.

FFVI-- Easily my favorite. While the gameplay wasn't what it could be, it made a good start of things to come gameplay wise. What really made it shine was the fantastic character development (best I've ever seen in a game), good story, incredibly music, and the best villain ever.

FFIV-- Really not a great game by todays standards, but I mainly like it for nostalgic reasons.

FFXI-- Oh yeah, I went there and put this game on my list. It may be unconventional but it is a great MMO (read: different from WoW). The crafting system was tedious but pretty nice, there is a good amount of early and mid game content and a lot of end game content, the community is great, and I love love love love the job/subjob system. Also, I was one of the few people that seemed to actually like Balista. :-p

FFVII-- I really didn't like this one the first time through, the graphics just disgusted me. If a technology is there but it's just doesn't look that great yet, just don't use it. True, it was good for the time but that doesn't mean it didn't look like ass. Other than that, it had an interesting story was fun. It definitely improved on gameplay where FFVI was lacking.

FFI-- Another game that makes it on my list for nostalgic purposes. It really doesn't hold up to todays standards and it isn't that fun. I like it mainly for the memories (though it was the 2nd FF game I played with IV being the first).

FFIX-- After the abomination that was VIII and the tech direction that VII took, this one was a welcome change. All in all, it was a good game; too bad it completely fell apart in the very end.

FFX-- It was a decent game, the gameplay wasn't great, the sphere grid sucked, and the story was beyond predictable. This game got an overwhelming meh.

FFXII-- The graphics in this game were beautiful. The writing was good. THe story wasn't bad. The gameplay was great. The world felt alive. Even the voice acting was incredibly high quality. Even with all that, I just didn't like the game. I don't know if it was because the story was so political or the license system was just silly (in that every character turned out to be the same-- wya to take the worst part of FFVI) but I just couldn't get myself into this game. I tried several times and each time I eventually just got very bored with the story and couldn't bring myself to progress any farther.

FFIII-- I just didn't care for this much. I played the DS version and it didn't appeal to me. Improving the graphics really didn't do anything to hold the game up to todays standards in a game. The job system was fun and a good start for other games, but it just wasn't that good.

FFVIII-- I actually prefer FFX-2 to this abomination. The story was beyond pathetic, the draw system was just irritating, the characters had absolutely no life at all and were very 2D, and, well, the game is just bad. I know I'll catch some criticism for this, but I expect FFXIII to measure up to this game.

VII -Surprised more people dont have this as number 1!! i played this after VIII though, and maybe i thought this was great because i generally found 8 to be sucky. Best thing about VII is the materia system, you can make the best combo's ever, plus the weapons provided a massive challenge at the end of the game.

IX - Loved the story in this one, was just a generally cool game, was also saddest (Vivi's side story and the black mages dieing). only major flaw with this is that i didnt really like kuja, bit of an emo.

 VI -Just finished this one! liked it, didnt find the story too deep tho, although it has awesome music.

X -Found X a bit annoying, i dont know wether it was the characters or the sphere system or the story or a combination of all 3! granted i loved the game, but its 4th on my list of FF's.

VIII - Least favorite by miles, the junctioning system was just boring, allowed for very little creativity. the world was practically empty (waste of space anyone?), also the whole game just went majorly downhill after the 1st disc, up until then it was ok.

those are the only ones i've played, although i should be borrowing 12 in a week from a friend of mine so i'm looking forward to that.

ff8... Sorry to defend this game, but did ppl play it all the way thru? Did ppl use the junction system to teh max?

I think the Junction system was brilliant and made you think alot. I think that was the problem... ppl liked materia where you can equip and level it up. Where as junction was alot to muck around with. I spend alot of my time in ff (ff7 -ff12) playing/planing the system be it materia, junction or the board style.

FF8 had alot ot offer. ie introduced the card games, GF (summons) leveling up where you could allocate skills for them to learn. And who could remember the time at Fishermans Horizon where you had the mini game where you made the Balamb Band. :D

I love the draw system, and getting the ingredients for remodeling your weapons.

And the story. Was brilliant. it had it all. Drama, backstabbing, conspiracy, flashbacks, time shifting, romance, anger, fun, joy etc. IT was by far the most mature of the ff realm.

I like Squall... because he was in a position he didn't want to be. He didn't want to be the protagonist, he didn't want to save the world, he just wanted to be himself and not be involved with drama. But he is put in this position that challenges him to fight his inner demons and think about other's. H is a very interesting character, who I think can identify with alot of ppl.

I think it comes down to a few things why ppl dislike ff8.

A) Junction system is too hard. Not materia.
B) Storyline. I think maybe the romance side?
C)Squall is not cloud.
D) not ff7

So, I really wonder if ppl played the game. I guess not everyone, Got...the game. But to me, it is my all time favorite (I played it 3 times), and it has some much to offer. I know there are alot of ppl that feel the same. I personally would give the game a 9. because it was great for it's time and gfx where awesome. There were some slow bits, but it's an rpg so it's just the norm. IF you do play ff8 give it a chance with an open mind. Plz play with the junction system... It becomes addictive once you understand it as it develops thru the game.

Edit

My FF top 10

1. FF8: I have my reasons

2. FF7: Cause Cloud Dates Barret at the Gold Saucer and Dresses in Drag :P

3.FF10: Tidus Is teh bestest @ Blizt

4.FF6: Kefka *hehe*

5.FF12: Love No Random Battles

6.FF3: Job System and Shrinking as a Midget :P

7.FF11: Online FF rox

8.FF9: Was a good game, back to basics.. Vivi was cool :D

9.FF4: I thought Cecil was a great character. Great story as well.

10.FF5: Butz and his Chocobo buddy save the day :D

VII - Played for about 15 minutes. Got bored of the random encounters and boring battles. Stopped.

III - Played for about 10 minutes. Got bored of the random encounters and boring battles. Killed by a random encounter with enemies that were much too strong and was forced to restart the whole game (since I hadn't come across a save point yet). Stopped.

Haven't played the rest. I never really understood Final Fantasy, I thought the game was dreadfully boring, but then I cut my teeth on Baldur's Gate and Icewind Dale. A completely different type of RPG, and definitely some of my favourite games.

7, 9, and 10 were all great. Close behind is 6. X-2 and 3-DS I liked as well, though not as much as the others. Only ones I've played so far.

Final Fantasy 4 - Definately by favorite due to storyline. No cool job classes and such, but the summons are real cool, and the storyline is the best FF.

Final Fantasy 7 - Materia made the game real fun. The story was good, and obviously an overall real great FF.

Final Fantasy 6 - My first FF I bought. Still really really good. The esper job/magic system was very good, and strong.

Final Fantasy 5 - Job classes made this very cool. Although I only played/beat it due to fan translations, it's still a very strong title. I have no idea why this never came to the US?

Final Fantasy XII - Great great Final Fantasy. After 7, I really never liked the series, but XII, despite a mediocre plot, had a great combat/licensing system.

Final Fantasy I - Obviously the first. Very good, and the multiple characters to pick at the starting was fun. Never beat Chaos at the end due to my copy erasing the savegame data.

Final Fantasy 8 - Not real good, imo. The junctioning system was OK, but the spellcasting/aquiring system was very very upsetting. Had this not been there, it'd of been great. Triple Threat was the best minigame/sidequest of the FF series (Condor Mtn, I think the name was in FF7, was also great). That made the game not too awefully bad. Story was OK, but nothing special.

Final Fantasy X-2 - last FF I played just before I rented XII. Man, this sucked. The dresspheres were OK, but outside of that, it played like a rehashed, crappier version of 8.


For the Game Boy incarnations (not the DS remakes):

Final Fantasy 2 - Monsters. Just great. That and robots made this game so great. Being able to double-up on a certain meat to increase your monster an entire generation was great.

Final Fantasy 3 - Grand in scale to mimic the console version, it was certainly alot of fun.

Never played FF1.