The Plugins menu is, in fact, completely new in Moodle 2.0, although it incorporates elements located elsewhere in earlier versions of Moodle. Let's take each item one at a time:
This link is the Moodle 2.0 equivalent to Modules | activities in Moodle 1.9. When expanded, it displays the settings pages for the activity modules. New here are:
File: Defaults for displaying a resource (has elements of the old Resource link).
Folder: Options for displaying a folder (formerly known as directory!).
Page: Defaults for displaying this page (has elements of the old webpage/text page).
URL: Defaults for displaying links to websites (previously included in Resource).
This equates to the Blocks link in Moodle 1.9 although we have lost sticky blocks now, as the new way of handling blocks lets us to make blocks sticky pretty much anywhere we want. New here is:
Tags: An option to show (or not) the course tagging features in the Tags block, allowing students to tag courses...