At least 50% of the time I don't even read the article, I just read the comments. I tend to be more interested in the conversation the posts generate than the posts themselves.
I would venture to guess I read the comments 90% more than the actual posts. The discussion (or the subject) will occasionally lead me to read the article in depth, but more often than not the discourse here is more enlightening overall. I can easily say HN is the only community where my behavior follows this model.