@Daz:
I feel like at this point "6 is the best one!" Is a sort of knee-jerk reaction akin to "Citizen Kane is the best movie".
(not that people don't legitimately like it of course)
Well, if you're going to pull out Citizen Kane, then yeah. When it was made, what it was made with, and the fact that no one had done anything like it before ARE factors to take into consideration. Take for instance that insane amazing opera sequence on the Super Nintendo, the ambition and scope and insanity of doing it on a thing that could only put out midis, on chibi sprite pixel graphics, and its a true amazing feat of wonder. Do the same thing as pre-rendered FMV on the PS1 with an actual singer recorded doing the lines, and it might be technically superior, but it also means less and loses a lot of the ambition and the heart, even if its technically vetter on an audio visual level.
Same with other aspects like Kefka's iconic laugh, or that one of the characters had street fighter controls, or that you drove around in a mech suit.
FF6 might not be the best in all areas. But when you count when it was made and what it did and what it set the precedents for, the number of characters it had, the music, the overall gaemplay, how well the dungeons distributed their loot, that puts it over the top.
If you play FF6 for the first time today almost 25 years later it might not 100% hold up, but its legacy IS part of it.
–- Update From New Post Merge ---
@Green_vs_Red:
I liked 10 and 10-2, Liked XII to an extent (thought the battle system was iffy though).
I hated 10 but really enjoyed X-2. It was super dumb but the job system was fantastic and the characters had fun, and that goes a long way in an rpg.
An RPG needs
-good characters
-good story
-good combat
If it has 2 out 3 it'll generally be fine and flaws in the other category can be overlooked if it excels enough. I love the Star Ocean games but the story is crap. But if it has all three, it can be fantastic.