[YoshimiTheEthereal]

Personally, I think FFVIII was the hardest for some reason. I had a had time with the final battle. I agree that X was the easiest, though.
As far as a system, I'm not sure what my favorite was. I think FFVII is a bit too complicated and takes a little too long to level up the materia. The Junction system just really got on my nerves. I guess I would have to say X, IX, and XII were my fave systems, since they are all different and good, and it just depends on my mood for which I think is best at the time.