FFIX of course. FFVIII was dry and dull by the time you got to the end because you could pwn anything that got in your way. It's story didn't help, it had depthless characters which fanboys and girls tried to overcomplicate (*cough*R=U *cough*). FFVIII had a pretty boy main character who they knew would win fans without any depth, FFIX had a funny likable character with a large amount of character depth and development.

All in all, IX>VIII, from personal expirence, all who deny this usually only liked FFVIII out of all FFs (not including VII they still usually like that).