When a blog entry has "Restrict entry viewing to Contacts and Blog Moderators" selected and the blogger (myself in this case) in the Blog Control Panel has "Guests may view your blog" checked, then guests can view all blogs whether private or not. Blogs can then never be really be private then. It doesn't make sense to call a blog private when it really isn't.
As a work around to make all blogs private (members and con, I'm going to have to create a user that will only be a "private blogger".
It would be great if the guests (or whoever) can see the blog overview page minus the private blogs.
Please see thread in Blog Questions, Problems and Troubleshooting