...Really?

I have only tried once, I got it on my PSP through PSN, and when I got to Disc 3 I just spent most of my time getting characters 4th level limit breaks and final weapons, I don't feel like trying again since Bizarro Sephiroth took forever

FFX hands Down..

IX (60 hours, completed) and X (150 hours, completed) were the ones I had the most fun with.

IV - I'm currently playing it but it's too average for current times
VI - I have yet to play past the middle of the game in my various tries, for various reasons, which is a shame because it seems so inspiring
VII - was too overwhelming (55 hours, completed)
VIII - was a love/hate thing (80 hours, completed)
X-2 - the Spice Girls alike theme killed it (35 hours, completed)
XII - 20 hours of fun, 100 hours that I forced myself through (120 hours, completed)

FF 4.

Always be 8 for me.

Story was deep and the characters were cool. Probably my favorite game of all time yet alone my fave in the ff franchise.

What I like about sephiroth is that he gets stronger as you level up, so once your at LV 99 or what not, he may be stronger than ruby at one point =D

Ruby Weapon > All versions of Sephiroth combined (Difficulty)

In no particular order
FF7
FFX
FF9

and in particular order

FF6
FF8
FF4

I didnt get FF9. Just didnt like the characters so decided to dislike it early on, never really gave it a chance. 8 will always be top one for me. Then number ten. X-2 was garbage, dont have a clue what they were trying to achieve. And 12 was not on par for me either.