I've started blogging with Word 2007 now and I must say it's a very good blogging tool. You have most of the usual Word features at your fingertips, you don't have to install any new software and publishing a post is quick and easy. The only nagging thing I have so far is that I can't find a way to add tags to posts. Word 2007 manages categories well, it even downloads them from your blog, but there doesn't seem to be a tags option.