To me it's a tossup between FFVII-IX just off the strength of their pre-rendered backgrounds. They're basically games full of paintings. 2D is charming and X and XII did some incredibly imaginative things with 3d, but it's gotta be one of the PlayStation games for me.

Not sure which one. IX's detail is off the charts, I really like VIII's more laid back feel to a lot of the locales and the more organic take on technology. As with other things, I'm going to go with VII because I felt like a lot of it was really good science fiction and just how memorable it was. For some reason sights like Midgar, the Junon Canon, Rocket Town and the Northern Crater made a really big impression on me, probably a bigger one than any other game.