I find my own interests reflected in your question, so here are some o-s projects that I am considering:
- SharpDevelop - they've gone a long way, and still a long way to go :-). I think some improvements for code navigation and code refactoring a la ReSharper (or even Eclipse) would be very cool.
- NHibernate - support for generics (although I think Ayende already has this covered); support tools - visual editors for xml configs, maybe a visual tool (VS addin?) that takes one of {model, mappings, database_schema } and generates the other two.
