My favorite would be X-2. It didn't matter how bad the game was cause the battles where awesome. It was a great last go of old school battling. They then switched to more movement and less control. FF12 was okay cause you could program your characters what to do, and in need you could throw in a command yourself.

My least favorite, is probably IX. Its not that I didn't like everything, there is just a lot that I didn't. First, the trance is BS and a waste of power. I prefer X's set up of limit breaks over all. Also the whole set job thing... I like to mix it up, which I won't say X-2 did it best. I'm saying Final Fantasy V did. The characters seemed weaker then others, and yes I did level all final fantasy characters to level 99. Even in 10 I mastered the sphere grid and had 99 SLVs.