Engadget, Macrumors, and here, for the most part (though I only comment here). The anti-Apple trolling is positively insane at Engadget, presumably because the average age of their commenters must be low, but it can get pretty bad at virtually any tech-oriented site, and even places like nytimes.com.

I definitely don't think 100% of Apple fans are immune to the above-decribed behavior: there are always some who aren't, especially if they're teenagers. You'll see more of that stuff now, because the space is polarized, and Apple fans have been put on the defensive. And yet I hardly ever see Apple fans producing hate-fueled criticism of other products and their fans. We receive way more of that stuff than we dish out.