Final Fantasy VII - Only my third favorite in the series, going against the theory that the first FF one plays is usually one's favorite. I've played through VII five or six times. It was the second RPG I ever played (Legend of Legaia (PLAY THIS GAME) was the first), discounting Action/RPGs (ie. Zelda).
Final Fantasy VIII - Second favorite in the series. There's something about the total atmosphere of this game that has me loving it where the majority feels the opposite way.
Final Fantasy IX - Took me a couple of playthroughs to really appreciate it. I really don't remember if I played this one first, or...
Final Fantasy VI - Fortunately I wasn't tainted by playing the PS1 FF's first, and I realise this is the best game in the series. I may have played this before FFIX.
Final Fantasy IV [Hardtype] - I really, really liked FF4. I need to purchase another copy of Chronicles so I can play through it again (as well as Chrono Trigger - better than any FF). It's probably my fourth favorite. Or fifth. It's a toss-up between that and IX.
Final Fantasy - I honestly didn't think the game was difficult, and I admit to using probably the easiest party imaginable (Two Fighters + BM + WM). Nevertheless, I've as of yet completed it only once and don't see myself going through it a gazillion more times.
Final Fantasy X - I HATED this game after the first time I played through it. After subsequent playthroughs, I now only dislike it.
Final Fantasy X-2 - B-L-A-H - Enough said.
Final Fantasy II - Lots of time spent in half-hour long battles with weak enemies alternatively attacking and healing my own party until I ran out of MP. Yay.

Final Fantasy V might have been between VI and IX if my friend hadn't moved away after I finished VI for the first time. I was borrowing Anthology from him, and had about half of it finished. I really need to finish it. In fact, I'm going to go spend some quality time with my emulator right now. Final Fantasy Tactics may also have been up there somewhere in the general vicinity of FFX. As to why I didn't finish it, same scenario as above for FFV. I have Crystal Chronicles, too, but the single player is too boring to give me incentive to finish, and none of my friends have the required (a)GBA (b)GBA/GC Link CAble (c)copy of FF:CC.