Not a popularity contest, but if you were to elect some in some categories, what would be the names?
Here are a few suggested categories.
The only criteria I’d insist on would be:
needs to be fully OSS, not a one-man show, have some people involved, have source available and with a well-know open source license (hopefully with no distinction between commercial and other uses)
Blog engines
Wikis
Web frameworks
WPF frameworks
Silverlight frameworks
Unit test frameworks (including spec?)
ASP.Net tools
more specialized frameworks
Scott Hanselman and Hamilton Verissimo de Oliveira