My favourite part of FF7 was actually the Midgar sequences. Midgar itself was an incredibly atmospheric city. The scene with the Don was just absolutely hillarious. Traveling around on the train from section to section. I wish Midgar had been expanded a little. There are many great locations through that game though. Unfortunately, there are some slow parts, but just don't quit, the game is well rewarding.
For those who said FF8 was better, I agree there. FF8 is still my favourite in the series; and I feel it is unfairly targeted by people who:
A) don't understand the gameplay (it is a little more complex than the other FF games).
B) Spent time drawing (you should refine magic from items bought, found, or won in battle, it is easier and more effective)
C) Are insecure about the romance story (and they label the game as "emo" as a result, even though it is not really). You might want to call this immaturity =)
I think a lot of people just wanted to dislike this game because it was the hip thing to do so among diehard FF7 and diehard Nintendo fans at some point. In the end, they miss out on enjoying what I think is the best FF experience to this day.
FF9 is also a fairly good one; it is similar in formula to FF7 in how the story is laid out; but the details are vastly different. In many cases the story off FF9 is a little more matured from FF7.
Then again, I'm the guy who liked every Final Fantasy game. The later FF games I have a bit of a gripe with, and that is the increasing focus on combat; FF10 had more battles and less story than FF7, 8, or 9. FF12 had even more battles and even less story than FF10, and FF13 had still more battles and less story than FF12.
FF7 may be no less linear than FF13; but FF7 does not have a rigid pace, FF13 does; in FF7 there's lots of little side things to do along the way - in FF13 there isn't, there's one path to move forward along there are no side things to do; no card games, no mini games, no real towns, etc....