Okay, I felt that this need a little more light on because even I'm confused on how FF7 is.

There are two good reasons why people like FF7. One is the story and the other is the gameplay.

First the story...

At first when I played it, the story was kinda dumb. It made perfect sense but there is no real complexity in the story of Final Fantasy 7. It felt as if everything was written on the spot basically, there was nothing to refer to in the beginning except rehashed stuff. In the end, people just seem to like the characters for what they look like. There were hardships and stuff with Cloud and everyone else but lets look at all the characters for one quick moment...

Cloud is a guy who was cloned or whatever... his history is pretty f'ed up, so on and so forth. I don't know about you but this has been repeated a whole mess of times and it gets pretty obvious when they try to slap it on you like 200 times. Each time they try to teach you something new about Cloud's "life", it is, for the most part, expected and predictable.

Tifa... well she has big breasts for some reason. She is kind of like a brother to Cloud and THEY HAVE NO LOVE CONNECTION WHAT SO EVER... but that's not important. What didn't catch me the first time I played FF7 was why I had her in my team in the first place... had nothing to do with the story in my opinion... I don't even like her for more than her attacks really..... and maybe her looks.

Aeris (or Earisu, whatever one you perfer) just came straight out of nowhere, people are looking for her to do experiments because she's "special." Not only that, she has a special type of Materia and she can do... stuff. The dying scene was pretty dramatic... but unfortunately, it was 2/10 out of what I've seen in my videogame experience (How would you like it if one of your best characters just die when you least expect it and feeling the pain the party to move on to find the answer to fix everything? It might be FF7... but it's more like Phantasy Star 2.)

As for the rest... who gives a crap?

Anyways, what I'm trying to say is that FF7 really doesn't have a novel sized story, it's just a short and sweet story that has everything you should already know.

Thus turning to gameplay, my reason why I play FF7 over the newer games.

What made FF7 so great is how many things you can do in the game. Not only that, the game didn't have much of a closed path, everything was spread around and there was a lot to do (not as much as FFX though). The attacks in this game allows so much more in the coolness factor, it makes you want to get more materia and more attacks just to kill off enemies. A lot of variations and a lot of visual awards for pulling things off.

This is probably why I feel that people play FF7 more... the story might have something to do with it, I don't know.... but in the end, I felt that grabbing the controller and running around killing stuff is fun.

In my opinion the story is very good, Especially the fact that in the first place you fight Shinra, but later on you encounter Sephiroth which is actually the main enemy. Cloud knows him and has a history with him that makes you want to find out what happenend there.
SPOILER And that Cloud never made it into soldier and that he placed himself instead of zack is pretty cool END SPOILER.

My motivation to play the game over and over is mainly the story..

The only thing that I felt that was unexpected was the whole Zack thing. Generally, Shinra is just the Team Rocket of the game (with the Turks being Jesse and James) and Sephiroth was the main villian... but once you cross over to Kalm, the game sets it right there and then, no huge surprises for the most part.

I haven't played the game in a while, but the thing that stood out about the story was how the bond in the party grew and strengthened all the way throughout the passage of the story. To start off with, everyone had his or her own agenda for joining. Barret to destroy Shinra and save the planet, Tifa because she wanted to be close to Cloud, Aeris because she had no where else to go, and she needed to find out about the Ancients. Red XIII wanted to go home. Yuffie wanted your materia. Cait Sith wanted to screw you over. Vincent wanted to take out Sephiroth and Cid was stranded with no where to go when the Tiny Bronco crashed.

However, the party pulled together with the various events that pushed them towards the final confrontation with Sephiroth. Their attitudes begun to change as they begun to realise that they, and they only they, had the power to stop Sephiroth from funking up the planet entirely. Aeris' death was meant to be Sephiroth's master stroke: Stop the only one with the magic know-how to summon the only thing that can counter him. It was his mistake though: It united the party. They all had a common bond of loss now because of that girl's death.

Also; There are parallel stories, while not of the depth of Final Fantasy VI, but still there. Cid getting into space, Barret redeeming himself with his home town, Vincent finding Lucrecia, Red XIII discovering the truth about his father, Seto. Cloud and Tifa piecing together the events in their past. Plus the Shinra subplot.

The gameplay is easy for a newbie to RPGs to pick up and play, and has enough depth so that more experienced veterans can wander about, find the secrets and play on.

The story can be simple if you sum it up, but if you look at it from each character's perspective, there's a tad more depth than you first think.

I agree with what Bahamut ZERO says. But when I look at it, its more of the storyline and the gameplay. ( To me, it is.)
It may have been confusing in the beginning...showing Aeris's face as she look up and the train going....but that was the suspense. Cloud's past may have been jumbled up with bits and scatter of evidence, but adding the other characters in flow smoothly with the storyline. It also leave a lot of mysteries behind and one by one, some are solved. Like Vincent's past and his involvement with Sephiroth or why Shinra wants Aeris. Other than that, the story unfolded itself slowly to the gamers without ruining the gameplay. The battling system was easy to understand and doing their limit breaks was no problem. There was added extra gameplay with the Shinra march or Gold Saucer, and yet, these little tidbits fitted perfectly with the storyline. It sorta gave you a reason why you had to do some of these tidbits. I mean, you can't sneak into a ship as a stow-away without uncovering some of Shinra's plans and joining them to see what they reveal first.
Not to make this longer, it sorta is both and why FF7 is played more.