FF VII was a revolutionary game and almost single-handedly won the platform wars for Sony in the 32 bit era. It was a massive coup for them at the time, as Square-Enix (then Squaresoft) was Nintendo's baby.
A deep story, excellent characters, great villains, and even some humor mixed in.
That being said... VI is still my favorite from the series, followed by X.
For all those areas in which FFVII was great, aside from the graphics and music, FFVI excelled. The characters and plot I felt were much, much deeper.
For instance, while Aerith's death in VII was indeed a very moving and memorable moment, one of the richest in the history of game-play, Cid's death in VI was equally so, especially the clear anguish it caused Celes, so much that she threw herself off a cliff. We never really got to see what kind of affect Aerith's death had on Cloud until Advent Children, as after the scene where her body is laid to rest in the pool, there's no expression of grief and little to no dialogue about it.
The opera from VI very nearly moved me to tears.
So yeah, both phenomenal games in their own right, but I carried VI with me afterwards a lot longer than VII.