STEEEEEEEAM.
Yes, this is a good thing. I pre-ordered it while it was on sale for $10.00; it's been a huge blast so far. The sale ended, unfortunately, so it's currently $15.00.
Super Meat Boy is extremely addictive, tough, and just plain fun all around. Don't take my word for it though: Metacritic assigned it 90% out of a possible 100%.
That's pretty freaking good.
I'm very impressed myself. It's hard to fathom a game on Newgrounds being remade and improved, then making it onto Steam, and even across to the big consoles. The multiplatform, critical appraise of Super Meat Boy is well deserved, though, as I haven't played a game like it since... well... Meat Boy.
Also, I know it's been out since October, but I just got it today and felt like spreading the word.
On a totally irrelevant note, happy 1st of December! :D