What is the recommended approach for monitoring changes to Solution Explorer items?

[mrpmorris]

I want to write a plugin/extension that shows the files/folders of all projects that are in the Solution Explorer.

I want it to react to the typical operations that are performed in the SE such as

1. load/unload Solution,
2. add/remove/rename/load/unload Project,
3. add/delete/rename/move Folder,
4. add/remove/delete/rename/move File.

What is the recommended approach for retrieving the items and receiving update notifications?