Oh man, Final Fantasy had such a huge effect on me growing up.
My first game in the series was the first game of the series, Final Fantasy for the NES. I got that game for Christmas one year and was allowed to play it for a grand total of one hour before we had to leave to visit family for Christmas dinner. That single hour was enough to hook me (even when I was ten, had no idea what a "roleplaying game" or what a character class was). I was drawn into the game so firmly that I took the manual with me. It had a walkthrough for the first half of the game in it because I guess the Japanese thought our puny American brains couldn't handle the game or whatever and I read every word of it to the point that by the time I was able to actually play the game the next day I felt like I had already been through it all.
I don't think I played very many games for my NES after I got that game. I was entranced by the world, the story, the character classes. Up until that point, I had never played a game where I could explore (relatively) freely. The fact that I could choose my own character classes was mindblowing for someone who had only played platformers and such up until that point. I played through it so many times that I could walk through Coneria, the first town, with my eyes closed.
Eventually the NES died. I had discovered emulation by then and was playing the later games in the series on my computer. They were fun: 5 is one of my top three in the series, 6 is just...godly. I wasn't a huge fan of 4 compared to some other people, but it was a fun game. The series got me interested in writing (my first "novel" was a novelization of Final Fantasy One's story. It was laughably, Wizzrobe-Bionicle-Doujinshi-level bad). It got me interested in reading when I discovered the fantasy genre.
My parents refused to buy me anymore consoles so it wasn't until I was in high school that I discovered the Playstation games.
I remember going to a friend's house and he had just gotten Final Fantasy VIII. He had basically just started the game and was roaming around Balamb Garden and the theme song played:
and I remember being blown away. It was
so gorgeous. Everything from the painted backdrops to the music. The battles seemed alive (when all you had played were the sprite games, the 3d games were mind-blowing). I learned that the game had come out for PC and that was all I wanted for my birthday. My computer was a piece of shit and it took upwards of a minute to transition between screens but I didn't care. I still played it. Everything about that game was gorgeous and vibrant and alive. Looking back with a critical eye, I realize that it had a lot of issues. The characters were meh, the story was...weird, and the junctioning system was too easy to abuse, but I didn't care then and I still don't. You know the way everyone on the internet has been freaking out about the VII remake? If they announced an VIII remake, that would be my reaction.
I ended up getting my first job solely so I could save up for a PS2 and play the recently-released FF10. I found that one disappointing, but I ended up playing the others for the playstation and loving 9 and even 12 a little bit. I also played all of the other great playstation RPGs like Star Ocean 2, FF: Tactics, Disgaea, etc.
So yeah: Final Fantasy's had a huge influence on getting me into writing, into reading, and getting me interested in getting my first job.
If I had to rank my top five in the numerical series, it would be 9, 8, 5, 6, 1.
EDIT - Wow, I sperged there. Sorry.