I currently treat my personal site as a lightweight “overview” page: who I am, what I work on, and a way to get in touch for opportunities. My blog, on the other hand, is where I explore ideas and interests that are mostly unrelated to my day job. I don’t really blog about my work; it’s more of an intellectual playground. For this reason, I keep the two separate.
However, I see the argument for keeping them together: It's good for branding, and can help someone get a complete picture of who you are when they land on the site... What does HN think?