Could anyone help me decide on which FF game to buy??? I don't know which one to get, there are too many like the Armored Core series

Humm... i would advise you to wait for the latest one....

Final Fantasy X. It's cheap (but it new for 200, at the most), it's one of their best, and it's not too hard to get into. Plus, it's not too hard to find at all. Of course, if you really want, you can wait for XIII, but you're gonna need a PS3, so get one of them, unless of course you have one.

I was gonna get XII, cuze it has really good graphics, it's for the PS2 most importantly, and it got a 5 out of 5 on Xplay

Depends on the type of gamer you are. If you like traditional RPGs with a good story and clean cut graphics, go for IX(9). It's really easy to get into, the soundtrack is amazing, and the story, characters, and gameplay is all really well done. Although it's fairly rare to find.

If you prefer strategy then go for FF Tactics(PS1) or Tactics Advanced(GBA). They're both really good games, although Tactics is a bit tough as you get further into the game.