Windows Live Gallery
Are you using Windows Live Writer for blogging? If not, why not? In addition to supporting rich WYSIWYG creation and editing of blog posts, it natively supports inserting pictures and automatically uploading them to your blog (if your blogging software supports the required API), inserting maps, tables, and tags for things like Technorati, you can also download a number of add-ins to provide even more functionality from the Windows Live Gallery:
The current lineup includes plug-ins for inserting video, code from Visual Studio, screenshots from the Vista snipping tool, and more. Definitely makes blogging a lot easier, and richer.