There's probably a lot of nostalgia in this, but I favor most, if not all, R/B/Y's tracks. I even have them in my (current) "game" playlist of 3000+ tracks! I think they're among the best during that gen, aside from the fact that I love 8-bit music.
But generally, all the Bike and Surf tracks are among my top favorites. The Bike gives that happy jingling you'd (well, I do) wanna have whenever travelling happily with friends across anywhere, while Surf gives a more soothing and calm tone.