We're using BlogEngine.net for this blog since it's open source and based on .NET 2.0. So far it works really well. One issue we ran into was that sometimes the stylesheet would not load and the blog would load without any styling applied at all. It happened very sparatically, so finding the issue has been tough. We've followed a post that told us to uncheck "Trim stylesheets" in the settings area. This seems to be working - we'll watch it and see if it resolves it permanently.
The helpful post was here:
http://www.codeplex.com/blogengine/Thread/View.aspx?ThreadId=21864