I stopped enjoying Final Fantasy after FFVII. I've played FF I-XI (X-2 included. XI is good but it's a MMORPG. Won't factor it in here).
FFIV is most likely the best one in the series. Storyline and character development-wise, it is years beyond itself. Plot twists abound, to boot. If you want the best of it, download an English-translated JP Rom. The American version for the SNES was kinda butchered and made real easy. Download a rom of it off of dgemu or something. There are some poseur translations that suck, so be careful.
I also highly HIGHLY recommend FF Tactics. The story is incredible. Probably the best PS1 RPG hands-down. You can buy it cheap online for around $20, to boot. You'd think a goodie like this would cost more, but it never got the acclaim the main series did.
Jam it back in, in the dark.