Notch takes Infiniminer
Sorry, bullshit. First Minecraft video posted by Notch on 2009-05-13. Infiniminer source release on 2009-05-16. This means that Notch had been working on Minecraft for some time before Infiniminer's source code was released. Also, Infiniminer:
So he didn't plagiarize anything more than the basic idea of a big world full of blocks. But Notch actually followed through to completion (more or less), while Infiniminer didn't.
As Steve Jobs was fond of saying, "Real artists ship."