The Pokémon + Ports handheld. It's hard even putting a list together here since I didn't really want to include the ported games but there is something to be said about getting to experience Mario + Final Fantasy + Donkey Kong Countries in handheld format. The GBA Metroid games are absolutely fantastic but if you were not a part of the Pokémon train I don't see the GBA library to be all that appealing overall. As a kid it was the most magical feeling to be under the covers with the GBA+Light attachment staying up too late trying to defeat the Elite 4 and claim my spot as League Champion!