Since WP 3.1 my plugins page does not have the 'update available' link for plugins. However, the Plugins menu item shows the number 7 behind it.
Behind 'updates' in the Dashboard menu it shows the numbr 6.
When I click on that updates link, it only says that "You have the latest version of WordPress."
There is also no 'updates' listing in the admin bar.
There are indeed plugins that must be updated.