It all depends on what my topic is about. I usually average about 10-20 on my photo topics/posts but on the every day life stuff, it's usually about 2-5. I'd be happy if the people that came and looked around would actually leave a comment.
If I got a comment a day (without offering a contest!), I would be thrilled. I'm still trying to figure out why some blogs get so many comments, and others get almost none.