Spider-Man 2 DS ... at least I think?
I was going to say Ocarina of Time, but I think I've only played that all the way through 2 or 3 times, then the expansion on Gamecube, but I never actually beat that stupid N64DD version that was on there.
As for Spider-Man 2, I've beat it a few times (still not sure about 5) and even picked it up again recently. It's not because it's so good, it's because it's an easy to pick up platformer with few chapters.
I've been trying to get all A scores recently, but the challenges are ridicuklously over hard (ESPzAECIALLY for bosses, which are usually keep all your health and win in under a minute).
It's actually a pretty average game, but like I said it's easy to pick up and to beat (minus the A scores) plus it's on a handheld, so I can play it while I do other things, which is why I beat it so many times.