In setting up WPMU sites for classes, I often wind up using the Text widget to add a bunch of important links - login, Dashboard, Add Post, Add Page, etc... to each site. Manually. I finally decided to save some time and just write a plugin that provides a generic widget to give the links on any site that uses it.
If you're not logged in, it provides a link to login:
If you are logged in, it gives you some handy links:
I'll eventually add a way to customize the widget (display Add Page? display Add Post? something else?) but for now, it's an easy fire-and-forget widget for the most common links used by people in a course blogging site.
Get your copy over at the WordPress plugin repository: Important Links Widget