Minecraft or
Terraria? Quite often these two games get compared, it's not hard to understand why: both involve exploring worlds made up of blocks which you can destroy and pick up, and in both of them you use the blocks and items found to craft other items.
When I first tried out Terraria a few months back, having already known Minecraft for a lot longer, I was quickly convinced Terraria was a superior game. And how could I not be? In Terraria there are many many more items to be crafted and acquired by the player, it also has a large variety of enemies (tough ones too) and bosses even. Overall you can feel the RPG component of the game is just much stronger than in Minecraft, in which you can get the top tier equipment during your first session and count all the different monsters with your hands.
So why do I think Minecraft is the best game then? Because it's the magic lasts longer (for ever, arguably). It is a better sandbox. In Terraria progressing through the game and killing the big bad bosses is all amazingly good fun, but once you reach the end you find out there's not much else to do and interest vanishes. You can still build and explore, sure, but the worlds of Terraria are small and in 2D: there's nothing new to surprise you when exploring and building in 2 dimensions gets old very fast. In contrast, Minecraft's worlds are practically infinite (you won't reach the edges without cheating) and 3-dimensional too, this means there's a lot of more variety in the geographic formations you can find, and in the stuff you can build too. Not matter for how long I have known and played Minecraft, there is always fun and wonder to be had, even from just jumping into a newly generated world and wandering about.
So I say Minecraft wins. But then again some may argue I have no business comparing the two.
(Also creepers. Terraria has no creepers, and creepers are the bomb.)