I think Little King's Story would have to be way up there, if not my top pick. It's the kind of game experience you NEVER see a second time, the sort of ingenious design and story wrapped up in a blanket of WTF that you just know can never be replicated. LKS is going to stick with me for decades, in heart and mind. It IS getting a sequel on Vita, but we haven't heard much about it yet, and it's not out. So I still consider LKS to be standalone.
Plus, the new game is ditching the unique style in favor of something I think looks less endearing and overall less interesting. And it's being made by a different studio. I'm already pretty sure it won't live up to the original.