In most environments, users will need to do something else with their PCs than playing multimedia, browsing Internet and reading PDFs, so maybe productivity/office apps should be a category on its own right. Now, I know you might go for the client route (Microsoft Office or any other package) or for the cloud route (and here we go with Google Apps or Office Live). But you should consider it into your list of basic apps to install.

Some years ago I would have added an email client along with the browser, but in these times, guess email clients only are useful to read that old stash of emails you don't want to erase from the times when you used Outlook Express/Windows Mail/Thunderbird/Eudora/Incredimail etc etc etc...