Spirit Tracks wins hands down for me. The PH system is great (as in, I had no real hope for touch-based games other than point-and-click until I played PH), and they even managed to fix a few annoyances (rolling, menu only uses one corner, menu actually pauses, and so on), story was fun, Zelda is an awesome sidekick (resulting in plenty of awesome cutscenes), and it's just a fun and addictive game, though it had 2 pretty big flaws known as the 4th and 5th Lokomo. I guess I should refer you to the game's specific thread if you want to know my complete opinion.
Platinum I never even got around to finishing, it honestly just bored me to death.
Scribblenauts sounded fun but was a bit of a disappointment (controls...).
Not really a big fan of the Mario RPGs (Unless you count the Paper Mario games, which still aren't amongst my top games, but still).
Stafy isn't released here (yet, I hope), but Kirby Superstar Ultra supposedly did come out (like over a year late, didn't matter since I bought the American version anyways), so I guess that gets 2nd place.
Haven't bought Kingdom Hearts yet, but I might one day when the price drops, though I doubt it would beat Spirit Tracks.