Okay...
Anything pre-FFVII won't be mentioned as most people won't know what I'm talking about. But for those who know, FFV... final boss... enough said.
In FFVII, the Emerald and Ruby weapons were tough. Ruby could be beaten easily with a combination of Hades and Hero items, as long as you kill off two of your party members pre-fight. Emerald was a bit trickier... you had to use less than 9 Materia per person. Still fairly easy if you know what you're doing... just cast Big Guard off of an Enemy Skill Materia and then use KOTR with W-Summon while the other two party members use Mime. The Limit Breaks are quite useful as well because if your party is maxed out their Limit Breaks will do massive amounts of damage. All in all, the Weapons were "difficult", but not impossible.
In FFVIII, Ultemecia was a cake walk. All you do is get the Laguna card, transform it into 100 Heroes, and voila. Cake.
In FFIX, X, and X-2 there isn't a boss worth mentioning. -.- Nine was too easy, ten was too easy to just train and whoop [spoiler=don't read if you don't wanna know] Jecht's ass, [/spoiler] and X-2 was... girly. I beat Vegnagun while eating a thing of Oreos.
To look for the hardest boss, you have to look to FFXII. It's long, drawn out, underdeveloped, and tends to become monotonous. However, the difficulty of this game makes it as annoying for FF noobs as it does make it the only reason to buy it for FF buffs. The final boss is fairly difficult, but if you've leveled your
whole party and not just three characters, like many people do, he's really not too bad. The hardest boss is actually very difficult to even get to, and if you don't have a walkthrough odds are you won't even see him. He's called Yiazmat and he's the final elite hunt. He's level 73 with over 50
million HP. At level 99 with a complete license board, this fight will take well over an hour... closer to two if you didn't level your characters previously. I'm not going to go into his attacks, or the way to beat him. It would take much more time than I have before I go to my tax appointment. But yeah, he's definately the hardest boss in any Final Fantasy. If you disagree, feel free to PM me and I'll prove you wrong with any statistics you need.
I am
the Final Fantasy nerd.

Oh, and honorable mention goes to the Chrono Cross endgame. No, not the boss. Though he's nearly impossible, after you beat him two or three times he's not so hard anymore. No... I'm talking about getting all the characters.
This post was edited by Alandariel on Mar 27 2007 11:23am