John Granger over at Hogwarts Professor has uploaded some new articles. I especially liked "Why Half-Blood Prince is the Best Harry Potter Novel." It's a bit long, but that's because Granger packs it with a ton of good stuff, ranging from Rowling's use of "the rules" for detective stories to her skillful use of narrative misdirection to keep readers on their toes. Granger also has some intriguing thoughts on what HBP reveals concerning which characters are actually good, which ones are really bad, and what exactly the Dark Lord is up to during Book 6. Some of his speculations may be a bit fanciful, but he does make some persuasive arguments.
There are several other new articles, including "Baptism Into a Sacrificial Death: The Christian Keys to Half-Blood Prince," which is also a pretty good read.
As always, the usual spoiler warnings apply: if, for some reason, you haven't yet read Half-Blood Prince, please spend time reading it before reading the articles.