Final Fantasy VII. I'll give it points for ambitiousness, but the plot's a half-coherent stew of extremely '90s cliches (magic is powered by lifeforce that's actually a stream of gel toothpaste under the ground, and that's why drilling for [strike]oil[/strike] Mako is bad!,) Cloud spends the first half of the game being annoying and the second half being bland, most of the best parts of the story were done better in Final Fantasy VI and Chrono Trigger, and the whole thing shows a lot of signs of being developed piecemeal and finished in a rush* (the character models look like they came from the Jaguar, no two pre-rendered cutscenes look alike, etc.) I'm not as ill-disposed towards it as I used to be, but all this "best game ever" talk? Nuh-uh.
* (If I had to guess, I'd say it was actually started for the N64 before Square had their falling-out with Nintendo and they didn't put enough work into updating the pre-existing material to mesh with the new stuff when they jumped to the Playstation.)