FF7 is my favorite game ever. Sorry if that is cliche, but I was introduced to it when I was 7 or 8 years old, and had no idea what it was because I was at my parents' friends' house, and their son let me play it. For 2-3 years I had to figure out what it was, and finally my brother (who didn't live with me) was borrowing it from a friend, and that's when I started a save over on my own memory card at his place, and got the name of the game. Finally I convinced my parents to buy me a copy, and I loved that game with all my heart.
FF8 I bought, and never finished, but enjoyed while I played. I would eventually like to replay it and finish it.
FFX I loved to death, and it is my favorite after FF7. Unfortunately, I got to the end boss battle, and for some reason stopped playing, so I'm not exactly sure what happens at the end of the game. Again, I'd eventually like to play through it again and finish it.
FF Mystic Quest for SNES is fantastic, and I encourage everyone to play it.
I briefly played FF1 on one of the PS1 compilation discs, and liked it while I played it.
FFX2 is bad juju. Got it for a birthday and played it for maybe an hour if I could stomach it that long.
FF7 DOC - Didn't really get into it, I'll try again one day.
FF7 Crisis Core - I liked it, but I got my PSP in the middle of already having my Xbox, and would rather play my 360.
FFXII, I played for maybe 30 minutes, just didn't get into it.
FF13, I have put about 45 hours into and I'm in Chapter 12 right now. I've had it since it came out, and I've just been too add to finish it, but I really like it, and while it's not the same as older FF's, and definitely not my favorite, I still think it is a good and fun game.
I'll buy FFXIII-2 no matter what, if not only for collecting purposes... I hope it's not like X-2, but I guess we'll see.
K great.