Disclaimer: some or all of these plug-ins are not Microsoft created or endorsed, and my pose a security risk by installing them without verifying their source.

1. Paste From Console - automatically formats and colorizes text copied from a console window for easy viewing on your blog. 
2. Paste from Visual Studio - pastes code copied from Visual Studio and preserves Visual Studio's coloring.
3. Insert Code - colorizes code you type appropriately for several common languages.
4. Flickr4Writer - inserts a picture to your blog from your flickr account, while keeping the picture hosted on flickr.
5. Picasa Image Plugin - inserts pictures and slideshows hosted on PicasaWeb.
6. Insert from SkyDrive - inserts links to your SkyDrive files into your posts.