Definitely Snow Boarding, but the G-Bike and Chocobo Racing come pretty close (there's a Chocobo Racing game for the PSX, but only one level is close to FFVII). The only game that never excited me substantially was Fort Condor - I'm just not that familliar with the whole C&C series...

What I really liked is that all of them were relovant in someway; That was cool, and the Gold Saucer isn't that removed from a plot either, becuase they are just video games in the area. I have yet to get past that damn afro guy...