Here's the case for Halladay to get the NL Cy Young this year:
The sub-3 ERA pitchers with more than 15 wins:
Halladay
Jimenez
Hudson
Wainwright
Out of those 4, Halladay has the most wins with 19. He also has the most K's, most IP, by far the most CG, and the most shutouts. Not to mention, his ERA happens to be the lowest of the 4.
He's given up the most hits, but when you couple that with his league-leading ERA, it shows that he's well focused in pressure situations. He's also given up the most HR, by a pretty big margin, but again, when you look at his ERA it says a lot. Plus he pitches in Citizens Bank Park, a known band box.
Only Wainwright has a lower WHIP than Halladay, by only .01. Halladay has walked FAR less batters than any of those 4. He's about 50% less than Wainwright, and about 75% less than the other 2.
The man is a beast, and to top it off, his team is leading the NL East by 3 games.
There's a couple weeks left, but he looks like the clear favorite right now.