Here's a hint. If the only thing that has hit your blog in the past week is your tweet-roll... it's probably all about NOISE.
I read a blog because the content contributes to my thought process. That may be because of who you are, but unless you are my kid, it's probably not the only reason. Your considered thoughts and content are a lot of what I care about. Maybe you can get that done in 160 characters. But I doubt that you can do it consistently.
In short, Twitter is a tool... but I don't think it's a BLOGGING tool.