Pao
It's still in development and not up to production use but it's quite unique in features. Basically, all the language constructs, such as assemblies, types, members, statements, expressions are treated as objects and are associated with rich operation options. You can enjoy features usually seen in graphical editors, such as multiple selection, multiple copy-paste, tagging, batch operation and very powerful search capability. It takes some getting used to but eventually might increase productivity. Right now, it only supports form applications though.
