I have 1 and 2 on Playstation, 3 on Nintendo DS, 4 5 and 6 on GameBoy Advance, 7 on Playstation, and 10 on Playstation 2 and I have still yet to finish an entire game.  I have just started playin FF X again so hopefully I will be able to get through it all the way to the end.  I still need to buy 8 9 and 12 (I have no desire to buy 11, I hate MMO's) and then i just am waiting for Square Enix to bring 13 and 13 Versus to the X360....so I can only hope so I can own the whole series.