Ive played FF5-10, and I'd say FF8 is my favourite. At the time I was playing FF5 I considered that to be almost as good as FF8, but I think that's just because I was enjoying the game so much at the time, it's not really so great, but I still liked it. FF7 and FF9 were good. I haven't quite completed FF10 yet, but that's the only one that could possibly overtake FF8 as my favourite; I'll have to wait until I complete it though before I make a final judgement.