Outlook is most used email exchange software.
In daily life you make life easier by using additional plugins to Outlook.
Some of the Plugin are here which make easier our work.
1)PrimoPDF: Its a print utility If you would like to archive you old mail as a PDF than this is the best plugin for you.Convert to PDF from any file you can print, including Microsoft® Word, Excel®, and PowerPoint® formats.
2)Sender Time Zone:If you have friends,Client office in different time zone than this a good plugin for outlook.makes easy work of dealing with recipients in multiple time zones - no more calculating times in your head. Once you open a message in Outlook, the plug-in shows the local time of the sender, difference from your time zone as well as thetime since the message was sent.
3)Desktop Search: Copernic Desktop Search, Google Desktop Search and X1 Search are the three most popular desktop search programs.Its search in your outlook mail and give you very precise result.One thing you have to take care about google desktop is its work when outlook is open.
Also See How you can Tag Your Outlook mail
4)SMSOfficer:With SMS Officer, you can send SMS messages from Outlook to any cell phone worldwide. The same service can also be used for setting up SMS reminders for any upcoming meeting / appointment in your Outlook Calendar. SMS Offices costs money but you get 10 free credits upon registration which are good enough for sending up to 10 text messages.
5)ESL Assistant – If English is not your native language, you can install the ESL Add-in from Microsoft Research to find common errors in your emails before you hit the Send button. Requires Silverlight.